nutrition, pregnancy,myresource.phoenix.edu/secure/resource/sci241r4/sci241... · 2005. 11. 30. ·...

(Henrik Sorensen/Photonica)

C H A P T E R 1 2 C O N C E P T S

� Over the 40 weeks of pregnancy, a single cell develops into a fullyformed child and the pregnant woman’s body undergoes manychanges to provide for the growing fetus.

� Energy, protein, water, vitamins, and minerals needs increase duringpregnancy.

� The developing child is vulnerable to nutrient imbalances and toxins.� High blood glucose or high blood pressure during pregnancy put

mother and child at risk.� Nutritional status, income, and age affect the risks to mother

and child during pregnancy.� Nutrient needs are even greater during lactation than pregnancy.� A newborn infant’s energy and protein needs are higher per unit

of body weight than at any other time of life.� Breast-feeding is the ideal way to nourish most infants.� Infants’ growth rates are the best measure of the adequacy of their diets.� After 4 to 6 months of age, solid foods can gradually be introduced

into the infant’s diet.

Should overweight women gain weightduring pregnancy?

Is a pregnant woman really eating for two?

Do pregnant women need vitamin and mineral supplements?

Is breast-feeding the best option for allnewborn infants and their mothers?

Ju s t A Ta s t e

USA Today

Study: Pregnant WomenEating Too Much FishBy Elizabeth Weise

Apr. 7, 2004—Of the 4 million babies born in the USAin 2000, more than 300,000 of them—and as many as600,000—may have been exposed to “unacceptable”levels of methyl mercury because their mothers ate a dietrich in fish, a study finds.

The new study, by researchers at the Office of Prevention,Pesticides and Toxic Substances at the EnvironmentalProtection Agency, repeats a warning by numerousstudies that the neurotoxin is particularly dangerous for growing fetuses.

Exposure to even low levels of mercury in utero can causedevelopmental problems and difficulties with visual andmotor integration.

To read the entire article, go to www.usatoday.com/news/health/2004-04-07-mercury-usat_x.htm.

405

12Nutrition, Pregnancy, and Infants

Babies Begin as a Single CellIn the First 8 Weeks All Organs Begin to FormBetween the 9th and the 40th Week, the Fetus Grows

and Organs Mature

A Woman’s Body Undergoes Many ChangesDuring PregnancyAdequate Weight Gain during Pregnancy Is Essential

for Mother and ChildMost Pregnant Women Don’t Need to Give Up Their Regular

RoutinesSome Physiological Changes of Pregnancy Have Uncomfortable

Side Effects

Diet During Pregnancy Affects Mother and ChildPregnant Women Have Increased Calorie, Protein, and Fluid

NeedsThe Need for Many Vitamins and Minerals Is Increased during

PregnancyThe Developing Child Is Vulnerable to Poor Nutrition

and Damaging Substances

Complications During Pregnancy PutMother and Baby at RiskGestational Diabetes Makes Delivery Difficult for Mother

and ChildPregnancy-Induced Hypertension Can Be Life-Threatening

Nutrition, Income, and Age Can AffectPregnancy OutcomeNutritional Health Is Important for Conception

and Pregnancy OutcomePoverty Increases the Risks of PregnancyPregnant Teenagers Face Economic, Social, Medical,

and Nutritional ProblemsOlder Mothers Are More Likely to Begin Pregnancy

with Health Problems

Nutritional Needs Are Greater DuringLactation than PregnancyMilk Production Varies to Meet the Demands of the InfantEnergy and Protein Needs Are Increased during LactationLactating Women Need More FluidsVitamin and Mineral Needs Are Increased during Lactation

An Infant’s Intake Must Provide forGrowth, Development, and ActivityInfants’ Energy Needs Must Provide for Their Rapid GrowthInfants Need a Higher Proportion of Their Calories from FatInfants Require Almost Twice as Much Protein per Kilogram

as AdultsInfants Lose More Water in Urine and Evaporation than AdultsIron Stores Help Meet Needs for the First 4 Months of LifeVitamin D Deficiency Is a Concern if Sun Exposure Is LowVitamin K Injections Are Given at BirthFluoride Supplements Are Needed if the Local Water Supply

Is Low in FluorideGrowth Is the Best Indicator of Adequate Nourishment

Infant Nutrient Needs Can Be Met by Breast Milk or FormulaBreast-Feeding Has Health and Nutritional Advantages

for Mother and ChildInfant Formulas Mimic the Composition of Human Milk

Solid Food Can Be Introduced Between 4 and 6 Months of Age

INTRODUCTION

uman development is an extremely complexprocess, but miraculously most babies are bornhealthy. In 9 months, a single cell grows and de-velops into a complete human being. During thistime all nutrients are delivered to the developing

child through the mother’s body. Her diet must provideeverything needed to grow a healthy baby. Too much ortoo little of a nutrient can affect the development of thechild and the outcome of the pregnancy. Toxins, like mer-cury, are also transferred from mother to child and can in-terfere with normal development of the baby.

H

406 Chapter 12 Nutrition, Pregnancy, and Infants

Babies Begin as a Single Cell

Whether you are 6 foot 4 or 5 foot 3, you started out as a single fertilized egg. The fer-tilized egg, which is called a zygote, divides rapidly to form a ball of smaller cells. Thecells begin to differentiate and to move to form structures. After about 2 weeks, it isstill not any bigger than the zygote, but consists of many cells and has begun burrow-ing its way into the lining of the mother’s uterus. After this implantation process iscomplete, the ball of cells is called an embryo. At first the embryo gets its nourishmentby breaking down the lining of the uterus, but soon this is inadequate to meet needsand the placenta begins to take over the role of nourishing it. The placenta is formedwhen branchlike projections grow from the implanted ball of cells into the lining ofthe uterus. These projections contain blood vessels that end up in close proximity tomaternal blood. The fully developed placenta contains a network of blood vessels thatallows nutrients and oxygen to be transferred from the mother’s blood to the baby andwaste products to be transferred from the baby to the mother’s blood for elimination(Figure 12.1). The placenta also secretes hormones necessary to maintain pregnancy.

In the first 8 weeks all organs begin to formThe embryonic stage of development lasts until the 8th week after fertilization. Dur-ing this time, the cells rapidly differentiate to form the multitude of specialized celltypes that make up the human body. They arrange themselves in the proper shapesand locations to form organs and structures. At the end of this stage the embryo is ap-proximately 3 cm long (a little more than an inch) and has a beating heart. All majorexternal and internal structures have been formed (Figure 12.2a).

Between the 9th and the 40th week, the fetusgrows and organs matureBeginning at the 9th week of development and continuing until birth, the developingoffspring is known as a fetus (Figure 12.2b). During the fetal period of development,structures that appeared during the embryonic period continue to grow and mature.The size of the fetus increases from about 3 cm to around 50 cm at birth. The fetalperiod usually ends after 40 weeks of gestation with the birth of an infant weighingabout 3 to 4 kg (6.6 to 8.8 pounds).1

Placenta

Amnioticcavity

Umbilicalarteriesand veins

Amnioticsac

Embryo

Umbilical cord

F I G U R E 1 2 . 1

During pregnancy, the amniotic sac and the fluid it contains protect the fetus, and theplacenta allows nutrients and wastes to be transferred between mother and baby.

When an egg from the mother isfertilized by a sperm from thefather, the genetic material fromeach parent combines to form agenetically unique individual. Onlyidentical twins have the samegenetic makeup. They develop froma single fertilized egg.

Implantation The process by whichthe cells derived from the fertilized eggembed in the uterine lining.

�*

Fetus The developing human from the9th week to birth. Growth and refinement ofstructures occur during this time.

�*

Gestation The time betweenconception and birth, which lasts about 9 months (or about 40 weeks) in humans.

�*

Embryo The developing human from 2 to 8 weeks after fertilization. All organsystems are formed during this time.

�*

Placenta An organ produced fromboth maternal and embryonic tissues. Itsecretes hormones, transfers nutrients andoxygen from the mother’s blood to thefetus, and removes wastes.

�*

Infants who are born on time but have failed to grow well in the uterus are said tobe small-for-gestational-age. Those born before 37 weeks of gestation are said to bepreterm or premature. Whether born too soon or just too small, low-birth-weight in-fants and very-low-birth-weight infants are at increased risk for illness and earlydeath.2 They often require special care and a special diet in order to successfully con-tinue to grow and develop. Survival improves with increasing gestational age and birthweight. Today, with advances in medical and nutritional care, infants born as early as25 weeks of gestation and those weighing as little as 1 kg (2.2 pounds) can survive.

A Woman’s Body Undergoes Many Changes during Pregnancy 407

F I G U R E 1 2 . 2

(a) At 5 to 6 weeks the embryo is less than 3 cm long but has a beating heart and the rudiments of all the majororgan systems. (b) At 16 weeks, the fetus is about 16 cm (6.4 inches) long and organ systems continue to mature.(a: Biophoto Associates/Photo Researchers; b: Meitchik/Custom Medical Stock Photo, Inc.)

(a) (b)

A Woman’s Body Undergoes Many Changes During Pregnancy

During pregnancy, a woman’s body must undergo many changes to support the devel-opment of her child. Her blood volume increases by 50%, and her heart, lungs, andkidneys work harder to deliver nutrients and oxygen and remove wastes. The placentadevelops to allow nutrients to be delivered to the growing fetus and the hormones itproduces orchestrate other changes. Body fat increases to provide the energy neededlate in pregnancy, the uterus enlarges, muscles and ligaments relax to accommodatethe growing fetus and allow for childbirth, and the breasts develop to prepare for lacta-tion. These changes all result in weight gain and can affect the type and level of phys-ical activity that is safe. In some cases they can also cause uncomfortable side effects.

Adequate weight gain during pregnancy is essential for mother and childA healthy, normal-weight woman should gain 25 to 35 pounds (11.4 to 15.9 kg)during her pregnancy. An average healthy baby weighs about 7 pounds at birth. Therest of the weight gained during pregnancy is due to changes in the mother’s body(Figure 12.3).

The rate of weight gain during pregnancy is as important as the total amount ofweight. Little gain is expected in the first 3 months, or trimester, of pregnancy—usuallyabout 2 to 4 pounds (0.9 to 1.8 kg). In the second and third trimesters, when the fetusgrows from less than a pound to 6 to 8 pounds, the recommended weight gain for themother is about 1 pound (0.45 kg) per week. Women who are underweight or over-weight at conception should also gain weight at a slow, steady rate (Figure 12.4). Weightgains of up to 40 pounds (18 kg) are recommended for women who begin pregnancyunderweight. Overweight women should gain less, only about 15 to 25 pounds (6.8 to11.4 kg) over the course of pregnancy.

Small-for-gestational-age An infantborn at term weighing less than 2.5 kg (5.5 lb).

�*

Preterm or premature An infant bornbefore 37 weeks of gestation.�*

Low-birth-weight A birth weight of less than 2.5 kg (5.5 lb).�*

Very-low-birth-weight A birth weightof less than 1.5 kg (3.3 lb).�*

Lactation Milk production andsecretion.�*

Trimester A term used to describe eachthird, or 3-month period, of a pregnancy.�*

Even women who areoverweight at the start ofpregnancy need to gain weightduring pregnancy to allow forthe growth of the child andexpansion of the mother’s bloodvolume and growth of othermaternal tissues.


Gaining too much or too little weight as well as being underweight or overweightcan affect the health of both mother and child.1 Being underweight by 10% or moreat the onset of pregnancy or gaining too little weight during pregnancy increases therisk of producing a low-birth-weight baby. Excess weight, whether present before con-ception or gained during pregnancy, can also compromise the outcome of the preg-nancy. The mother’s risks for high blood pressure, diabetes, a difficult delivery, and acesarean section are increased by excess weight, as is the risk of having a large-for-gestational-age baby. However, dieting during pregnancy is not advised even for obesewomen. If possible, excess weight should be lost before the pregnancy begins or, alter-natively, after the child is born and weaned.

Total

Fetus

Amniotic fluid

Placenta

Uterus

Maternal blood

Breast tissue

Extracellular fluids

Maternal fat

25-35 lb

7-8 lb

2 lb

1-2 lb

2 lb

3-4 lb

2 lb

4 lb

4-11 lb

10

20

30

40

50

0 5 10 15 20 25 30 35 40 45

Wei

ght g

ain

(lb)

0

Underweig

ht

Normal

weight

Overweight

Gestation (weeks)

F I G U R E 1 2 . 3

The weight gained by the mother during pregnancyincludes increases in the weight of her tissues aswell as the weight of the fetus, placenta, andamniotic fluid.

F I G U R E 1 2 . 4

The same pattern of weight gain is recommended for women who are normal weight,underweight, or overweight at the start of pregnancy, but the recommendations for total weight gain are different. (Adapted from Committee on Nutritional Status DuringPregnancy and Lactation. Nutrition During Pregnancy. Washington, D.C.: NationalAcademy Press, 1990.)

Cesarean section The surgicalremoval of the fetus from the uterus.�*

Large-for-gestational-age An infantweighing greater than 4 kg (8.8 pounds) at birth.

�*

Most women lose all but about 2 pounds of the weight gainedduring pregnancy within a year ofdelivery. Typically, a woman losesabout 10 pounds at delivery andanother 5 pounds during the firstweek after delivery. Further weightloss requires a balanced low-caloriediet combined with moderateexercise.

Most pregnant women don’t need to give uptheir regular routinesPregnant women may need more rest, but they usually don’t need to give up their reg-ular exercise routines. Physical activity during pregnancy improves overall fitness,mood, and body image; reduces stress; improves digestion; prevents excess weightgain, low back pain, and constipation; reduces the risk of diabetes; and speeds recov-ery from childbirth. Therefore, for healthy, well-nourished women, carefully chosenmoderate exercise is recommended during pregnancy. Women who were physically ac-tive before their pregnancy can continue their exercise programs, but women whobegin an exercise program after becoming pregnant should start slowly, with low-in-tensity, low-impact activities such as walking.3 During pregnancy, the risk of injury isgreater because women weigh more and carry that weight in the front of their bodieswhere it can interfere with balance and place stress on the bones, joints, and muscles.Activities that have a risk of abdominal trauma, falls, or joint stress, such as contactand racquet sports, should be avoided (Figure 12.5).4 To ensure adequate delivery ofoxygen and nutrients to the fetus, intense exercise should be limited. Guidelines havebeen developed to minimize the risks and maximize the benefits of exercise duringpregnancy (Table 12.1).

Some physiological changes of pregnancyhave uncomfortable side effectsDuring pregnancy, a woman experiences changes in the amount and distribution ofbody fluids and the types and levels of certain hormones. These physiological changescan cause uncomfortable side effects. Most of these problems are minor, but in somecases they may endanger the mother and the fetus.

Blood volume increases during pregnancy During pregnancy,blood volume expands to nourish the fetus, but this expansion may also cause theaccumulation of extracellular fluid in the tissues, known as edema. Edema is char-acterized by swelling, particularly in the feet and ankles (Figure 12.6). It can be un-comfortable but does not increase medical risks unless it is accompanied by a risein blood pressure. Reducing water or salt intake is not beneficial in preventingedema.

A Woman’s Body Undergoes Many Changes during Pregnancy 409

F I G U R E 1 2 . 5

During pregnancy, exercising in the water canreduce stress on joints and help keep thebody cool. (Tracy Frankel/The Image Bank/Getty Images)

T A B L E 1 2 . 1Moderate Exercise Is Recommended for Most Healthy Pregnant Women

• Check with your physician before beginning an exercise program duringpregnancy

• Drink plenty of liquids before, during, and after exercise• Increase your activity gradually and limit strenuous exercise• Exercise regularly, at least three times per week, rather than intermittently• Stop exercising when you are tired• Avoid exercising in hot or humid environments• Choose activities that have a minimal risk of falls or abdominal injury• Avoid exercises that require lying on your back• After recovering from delivery, gradually resume prepregnancy exercise

routines

Adapted from American Dietetic Association. Nutrition and lifestyle for a healthypregnancy outcome. J. Am. Diet. Assoc. 102:1470–1490, 2002.

F I G U R E 1 2 . 6

Edema in the feet and ankles is a commonproblem during pregnancy. Elevating the feetwill help reduce swelling. (Elie Bernager/Stone/Getty Images)

Edema Swelling due to the buildup of extracellular fluid in the tissues.�*


Hormonal changes cause morning sickness Morning sicknessis a syndrome of nausea and vomiting that occurs during pregnancy. The term issomewhat of a misnomer because symptoms can occur anytime during the day ornight. It is thought to be related to the hormonal changes of pregnancy and may bealleviated to some extent by eating small, frequent snacks of dry starchy foods,such as plain crackers or bread. In most women symptoms decrease significantlyafter the first trimester, but in some cases the symptoms last for the entire preg-nancy and, in severe cases, may require intravenous nutrition to assure that needsare met.

Digestive complaints are common as muscles in the GItract relax The hormones produced to relax the muscles of the uterus also relaxthe muscles of the gastrointestinal tract. This relaxation along with the crowding ofthe organs by the growing baby can cause digestive complaints such as heartburn andconstipation. Heartburn is common because the relaxation of the sphincter betweenthe stomach and the esophagus allows the acidic stomach contents to back up into theesophagus, causing irritation. The problem gets more severe as pregnancy progressesbecause as the growing baby crowds the stomach, its contents are more likely to backup into the esophagus. Heartburn can be reduced by avoiding substances such as caf-feine and chocolate that are known to cause heartburn, and eating many small mealsthroughout the day rather than a few large ones. Limiting intake of high-fat foods,such as fried foods, rich sauces, and desserts, which leave the stomach slowly, can alsohelp reduce heartburn. Because a reclining position makes it easier for acidic juices toflow into the esophagus, remaining upright after eating can also help.

Constipation is also common during pregnancy because the relaxed muscles of thecolon are less efficient. Maintaining a moderate level of physical activity and con-suming plenty of fluid, as well as high-fiber foods such as whole grains, vegetables,and fruits, are recommended to prevent constipation. Hemorrhoids are more com-mon during pregnancy, as a result of both constipation and physiological changes inblood flow.

So, What Should I Eat?

To ease the nausea of morning sickness• Try some crackers or dry toast in the morning—before you even get out of bed• Have half your lunch now and half later• Sip water throughout the day

To reduce constipation• Focus on fiber by eating whole grains and lots of fruits and vegetables• Keep all of you moving by getting regular exercise• Drink an extra glass of water after each meal

To prevent heartburn• Relax and enjoy your meal—you won’t have time once the baby is born• Save your fluids for between meals so your stomach doesn’t get too full• Skip the spicy, fatty foods• Eat sitting up and stay upright to let gravity keep food in your stomach

Morning sickness Nausea andvomiting that affects many women duringthe first few months of pregnancy and insome women can continue throughout thepregnancy.

�*

Diet During Pregnancy Affects Mother and Child

Diet during Pregnancy Affects Mother and Child 411

During pregnancy the mother’s intake must provide all the nutrients needed for thegrowth and development of the baby while continuing to meet the mother’s needs.Because the increase in calorie requirement is proportionately smaller than the in-creased need for protein, vitamins, and minerals, a nutrient-dense diet is essential. Be-cause the developing child is vulnerable, deficiencies and excess of nutrients as well asother damaging substances must be avoided during pregnancy.

Pregnant women have increased calorie needsIt is often said of a pregnant woman that she is eating for two. Although she doesn’tneed to eat twice as much, during most of the pregnancy she does need to eat morethan a nonpregnant woman. This extra energy is needed to provide for the baby andnew maternal tissues. During the first trimester, total energy expenditure changes lit-tle, so the EER is not increased above nonpregnant levels. During the second andthird trimesters, an additional 340 and 452 Calories per day, respectively, are recom-mended (Figure 12.7). This is the number of calories contained in a snack such as asandwich, an apple, and a glass of milk.

Pregnant women need more proteinDuring pregnancy blood volume increases, the placenta develops and grows, theuterus and breasts enlarge, and the baby grows from a single cell to a fully formed in-fant. Protein is needed for the structure of new cells so this growth increases the needfor dietary protein. An additional 25 grams of protein per day above the RDA fornonpregnant women or 1.1 grams per kilogram per day is recommended for the sec-ond and third trimesters of pregnancy. For a woman weighing 136 pounds (62 kg),this increases protein needs to about 75 grams per day (see Figure 12.7). This is the

Riboflavin

Niacin

Vitamin B6

Folate

Vitamin B12

Calcium

Phosphorus

Magnesium

Iron

Zinc

Iodine

Selenium

Percent increase0 20 40 60 80 100

Energy

Protein

Vitamin A

Vitamin D

Vitamin E

Vitamin K

Vitamin C

Thiamin

KeyPregnantLactating

F I G U R E 1 2 . 7

This graph illustrates the increase inrecommended nutrient intakes for a 25-year-oldwoman during the third trimester of pregnancyand during lactation. The RDA for iron duringlactation is equal to half the RDA fornonpregnant, nonlactating women.

A pregnant woman is eatingfor two because she mustprovide for all her nutrientneeds as well as for those ofthe fetus. But eating for twodoesn’t mean eating twice asmuch. The equivalent ofhaving 2 lunches every daytoward the end of pregnancywill provide the extra energyand nutrients needed.


amount of protein in three servings of milk or yogurt and two servings of meat. Fol-lowing the Food Guide Pyramid recommendations for pregnant women can ensurethat these needs are met (Figure 12.8).

Fluid needs are increased slightly duringpregnancyThe need for water is increased during pregnancy because of the increase in blood vol-ume, the production of amniotic fluid, and the needs of the fetus. During a pregnancya woman will accumulate about 6 to 9 liters of water. Some is intracellular, but most isdue to increases in the volume of blood and interstitial fluid between cells. The needfor water is therefore increased from 2.7 liters per day in nonpregnant women to 3liters per day of total water—that from both food and beverages.5 Adequate fluid con-sumption throughout pregnancy is also important in preventing constipation. Despitechanges in the amount and distribution of body water there is no evidence that the re-quirement for potassium, sodium, or chloride is different from that of nonpregnantwomen.

The need for many vitamins and minerals is increased during pregnancyIn order to grow new tissues in the mother and the child, the requirements for manyvitamins and minerals increase during pregnancy. The need for B vitamins, such asthiamin, niacin, and riboflavin, increases as energy needs increase. The requirementsfor vitamin B6 and zinc rise to meet the needs for increased protein synthesis. The re-

Food Guide PyramidA Guide to Daily Food Choices

Fats, oils, & sweetsUse sparingly

Milk GroupNonpregnant, 2 servingsPregnant, 3 servingsLactating, 3 servings

Meat GroupNonpregnant, 5 oz.

Pregnant, 6 oz.Lactating, 7 oz.

Fruit GroupNonpregnant, 3 servings

Pregnant, 3 servingsLactating, 3 servings

Bread GroupNonpregnant, 7 servings

Pregnant, 8 servingsLactating, 10 servings

Vegetable GroupNonpregnant, 3 servingsPregnant, 4 servingsLactating, 4 servings

Key Fat (naturally occurring and added) Sugars (added)These symbols show fats, oils, and added sugars in foods.

USDA, 1992

F I G U R E 1 2 . 8

The Food Guide Pyramid can be used for diet planning during pregnancy and lactation. Shown here are the recommended servings for a 25-year-old woman beforepregnancy and during pregnancy and lactation. (U.S. Department of Agriculture, Home and Garden Bulletin No. 252, 1992)

quirements for calcium, vitamin D, and vitamin C increase to provide for the growthand development of bone and connective tissue. The needs for folate, vitamin B12,zinc, and iron are increased to support the formation of new maternal and fetal cells.For many of these nutrients, intake is easily increased when energy intake is increasedto meet needs, but for others there is a risk that inadequate amounts will be consumed.

Increased calcium absorption helps meet needs Over thecourse of gestation the fetus accumulates about 30 grams of calcium. Most of this isdeposited during the last trimester when the fetal bones are growing most rapidly andthe teeth are forming. Many women have trouble consuming enough calcium to meettheir own needs, let alone enough to provide this amount for the fetus. Fortunatelythey don’t need to eat any more than is recommended for nonpregnant women be-cause calcium absorption increases during pregnancy. At one time there was concernthat the calcium needed by the fetus would come from maternal bones if intake wasnot adequate. It is now known that the increased need for calcium does not increasematernal bone resorption, and studies have found no correlation between the numberof pregnancies a woman has had and the density of her bones. The AI for calcium forpregnant women age 19 and older—1000 mg per day—is therefore not increasedabove nonpregnant needs.6 The AI for calcium can be met by consuming three tofour servings of milk or other dairy products daily. Women who are lactose intolerantcan meet their calcium needs with yogurt, cheese, reduced-lactose milk, calcium-richvegetables, calcium-fortified foods, and calcium supplements.

Vitamin D is needed to ensure adequate calcium ab-sorption Adequate vitamin D is essential to ensure efficient calcium absorption,but the recommended intake for vitamin D is not increased above nonpregnant lev-els. Pregnant women who receive regular exposure to sunlight can make sufficient vi-tamin D in their bodies. If exposure to sunlight is limited, dietary sources such asmilk must supply the needed amounts. Inadequate vitamin D may be a particularproblem in African American women because their consumption of milk, which is agood source of vitamin D, is often low due to lactose intolerance and their darkerpigmentation reduces the synthesis of vitamin D in the skin. It is also a concern inwomen who remain covered when outdoors. If sufficient vitamin D is not consumedin the diet, careful supplementation should be considered. Most prenatal supple-ments provide 10 �g of vitamin D, which is twice the AI but well below the UL forpregnancy of 50 �g.6

Vitamin C is needed for healthy connective tissue VitaminC is important for bone and connective tissue formation because it is needed for thesynthesis of collagen, which gives structure to skin, tendons, and the protein matrix ofbones. Vitamin C deficiency during pregnancy increases the risk for premature birthand other complications. The RDA is increased by 10 mg per day during pregnancy.7

The requirement for vitamin C can easily be met with foods such as strawberries andcitrus fruit; supplements are generally not necessary.

Low folate increases the risk of neural tube defects Folateis needed for the synthesis of DNA, and thus, for cell division. During pregnancy,cells multiply to form the placenta, expand maternal blood, and allow for fetalgrowth. Adequate folate intake is crucial even before conception because rapid cell di-vision occurs in the first days and weeks of pregnancy.

Folate deficiency can cause megaloblastic anemia in the mother. In the baby, lowfolate levels increase the risk of abnormalities in the formation of the neural tube. Theneural tube is the portion of the embryo that develops into the brain and spinal cord.During development, neural tissue forms a groove; the groove closes when the sidesfold together to form a tube (Figure 12.9). This neural tube closure occurs between 21and 28 days of development. If it does not occur normally, the infant will be bornwith a neural tube defect, such as spina bifida, a defect in which the neural tube doesnot close completely (see Chapter 8). Folate continues to be important even after the


RememberMegaloblastic anemia occurs when redblood cells are unable to divide normally,causing abnormally large immature andmature red blood cells and a reducedcapacity to transport oxygen.

*

Neural tube A portion of the embryothat develops into the brain and spinal cord.�*

The incidence of vitamin Ddeficiency has been increasing inall segments of the population. Onestudy found that over 40% of AfricanAmerican women of childbearingage were vitamin D deficient.

The causes of neural tube defects arenot fully understood, but studies haveshown us that 50 to 70% of neuraltube defects can be prevented byconsuming sufficient amounts of folicacid.The incidence in the UnitedStates has been reduced by about25% since the introduction of folicacid fortified grains.


neural tube closes. Inadequate folate intake is associated with premature and low-birth-weight births and fetal growth retardation.8

Because the neural tube closes so early in development, often before a woman evenknows she is pregnant, the DRIs recommend that women capable of becoming preg-nant consume 400 �g daily of synthetic folic acid from fortified foods, supplements,or a combination of the two, in addition to consuming a varied diet rich in naturalsources of folate (see Chapter 8, Piece it Together: Is it Hard to Meet Folate Recom-mendations?). During pregnancy, the RDA is 600 �g of dietary folate equivalents perday.9 Natural sources of folate include orange juice, legumes, leafy green vegetables,and organ meats. Fortified sources include breads, cereals, and other enriched grainproducts. Folic acid supplements can also be used to meet this goal. Most prenatalsupplements contain 400 �g of folic acid.

Vitamin B12 is needed to activate folate Vitamin B12 is essentialfor the regeneration of active forms of folate, so a deficiency of vitamin B12 can also re-sult in megaloblastic anemia. Based on the amount of vitamin B12 transferred fromthe mother to the fetus during pregnancy, and the increased efficiency of vitamin B12

absorption that occurs during pregnancy, the RDA for pregnancy is set at 2.6 �g perday.9 This recommendation is easily met by a diet containing even small amounts ofanimal products. Vegetarian diets are generally safe for pregnant women but vegansmust consume foods fortified with vitamin B12 or take vitamin B12 supplements tomeet the needs of mother and fetus.

Zinc is important for growth and development Zinc is in-volved in the synthesis and function of DNA and RNA and the synthesis of proteins.It is therefore extremely important for growth and development. Zinc deficiency dur-ing pregnancy is associated with an increased risk of fetal malformations, prematurebirth, and low birth weight.10 Because zinc absorption is inhibited by high iron in-takes, iron supplements may compromise zinc status if the diet is low in zinc. TheRDA is 11 mg per day for pregnant women 19 years of age and older.11

Iron needs increase by 50% during pregnancy Iron needs arehigh during pregnancy to provide for the synthesis of hemoglobin and other iron-con-taining proteins in both maternal and fetal tissues. The RDA for pregnant women is27 mg per day, which is 50% higher than the 18 mg per day recommended for non-pregnant women.11 Many women fail to meet their iron needs even when not preg-nant. Because low iron stores are so common among women of childbearing age,women often start pregnancy with diminished iron stores and quickly become defi-cient. This occurs despite the fact that iron absorption is increased during pregnancyand iron losses are decreased due to the cessation of menstruation. Iron deficiencyanemia during pregnancy has been associated with an increased risk of low birthweight and preterm delivery.12 Babies born at term usually have adequate iron storeseven if the mother is deficient. But, because most of the transfer of iron from motherto child occurs during the last trimester, babies born prematurely may not have hadtime to accumulate sufficient iron.

It takes an exceptionally well-planned diet to meet iron needs during pregnancy. Redmeats, leafy green vegetables, and fortified cereals are good sources of iron. Foods that en-hance iron absorption, such as citrus fruit and meat, should also be included in the diet.Iron supplements are typically recommended during the second and third trimesters.

Prenatal supplements are typically recommended Evenwhen a healthy diet is consumed it is difficult to meet all the vitamin and mineralneeds of pregnancy. Generally supplements of folic acid are recommended before andduring pregnancy, and iron supplements are recommended during the second andthird trimesters.1 A multivitamin and mineral supplement may also be necessary forthose whose food choices are limited, such as vegetarians, and for those whose needsare very high, such as pregnant teenagers. A prenatal supplement, however, must betaken in conjunction with, not in place of a carefully planned diet.

Day 19

Day 20

Day 22

Day 28

Neuraltissue

Fold to forma groove

Sides almosttouch to forma tube

Neural tubeclosurecomplete

F I G U R E 1 2 . 9

During embryonic development, a flat plate of neural tissue forms a groove and then theedges fold up and join to form the neural tube,which will become the brain and spinal cord.

Pregnant women don’tnecessarily need vitamin andmineral supplements, but theyare typically recommendedduring the last two trimesters.The supplement can help ensurethat a pregnant woman andher baby are getting all themicronutrients they need.


P I E C E I T T O G E T H E R

Nutrient Needs for a Successful PregnancyTina is 4 months pregnant. From the start—before she tried toconceive—she has been careful about her diet. She has paidattention to her folate intake by eating plenty of leafy greens,which are naturally high in folate, and enriched grain products,which are fortified with folic acid. Now that she is entering hersecond trimester, her doctor is concerned that her diet may bedeficient in iron and has prescribed a prenatal supplement.Tina follows his advice and takes the supplement, but she iscurious about whether her diet meets the nutrient needs ofpregnancy without supplements. She records her intake for atypical day:

Food Guide Pyramid Food Group/Serving

Breakfast1 cup corn flakes 1 grain

with 1 cup reduced-fat milk 1 milk3/4 cup orange juice 1 fruit1 cup decaffeinated coffee with fats, oils, and sweets

sugar and cream

LunchTuna sandwich

3 oz tuna 1 meat2 tsp mayonnaise fats, oils, and sweets2 slices white bread 2 grain

20 french fries 2 vegetable1 can orange soda fats, oils, and sweets3 chocolate chip cookies 1 grain1 apple 1 fruit

Dinner3 oz chicken leg 1 meat1/2 cup peas 1 vegetable1 piece corn bread 2 grain1 tsp margarine fats, oils, and sweets1 cup lettuce and tomato salad 1 vegetable1 Tbsp dressing fats, oils, and sweets1 cup reduced-fat milk 1 milk

Tina’s current diet meets the recommendations of the FoodGuide Pyramid for a nonpregnant woman, but during hersecond and third trimesters, she will need an extra 340 to450 Calories per day. To obtain this extra energy she shouldadd a serving of vegetables, a serving of milk, an ounce ofmeat, and a serving of grain products.

WHAT NUTRIENTS ARE PROVIDED BY THESE ADDITIONS?

An added serving of whole grains will add iron, zinc, fiber,and B vitamins. The extra serving of vegetables will addfolate, fiber, and vitamin C or A. The extra serving of dairyproducts will add protein, riboflavin, vitamin D, andcalcium. Even though the recommendation for calciumintake is not increased during pregnancy, most youngwomen do not meet calcium needs, and three servings fromthis group provide about 1000 mg, which is the AI foryoung adults. The extra meat adds protein, and if it is fromred meat, it provides an excellent source of absorbable ironand zinc as well as vitamins B12 and B6.

TINA IS OVERWEIGHT. SHOULD SHE STILL ADD THESEFOODS TO HER DIET? WHY OR WHY NOT?

Your answer:

DOES TINA’S DIET MEET THE IRON NEEDSOF PREGNANCY WITHOUT SUPPLEMENTS?

Her current diet provides 10.5 mg of iron—significantly less than the RDA of 27 mg for pregnant women.

COULD TINA MODIFY HER DIET TO MEET THE IRONRECOMMENDATIONS WITHOUT INCREASING HER

CALORIE INTAKE? SUGGEST SOME CHANGES.

Your answer:

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The developing child is vulnerable to poornutrition and damaging substancesCells that are rapidly dividing, differentiating, and moving to form organs and otherstructures are particularly vulnerable. Anything that interferes with development cancause a baby to be born too soon or too small or can result in birth defects. Any chem-ical, biological, or physical agent that causes birth defects is called a teratogen. Theplacenta prevents some teratogens from passing from the mother’s blood to the em-bryonic or fetal blood, but it cannot prevent the passage of all hazardous substances.Because the majority of cell differentiation occurs during the embryonic period, this isthe time when exposure to teratogens can do the most damage, but vital body organscan still be affected during the fetal period (Figure 12.10). Each organ system devel-ops at a different rate and time, so each has a critical period when exposure to a terato-gen or other insult can disrupt development causing irreversible damage. If thedamage is severe, it may result in a spontaneous abortion or miscarriage.

Off the Label: What’s in YourPrenatal Supplement?

Most pregnant women leave their first prenatal doctor’svisit with a prescription for a prenatal vitamin and mineralsupplement. What’s in these supplements? Do they meet allthe needs of pregnancy?

A look at the supplement label shows you that a typicalprenatal supplement contains more than 15 vitamins andminerals. It contains enough folate and iron to meetrecommendations and the same can be said for many of theother nutrients, but taking a prenatal supplement does notmean you can ignore your diet. Even though they supplymany vitamins and minerals at levels that meet or slightlyexceed the recommended intake for pregnancy, some are present in amounts that do not meet the needs ofpregnancy, and others are missing altogether. For example,the tablet shown in the table contains only 200 mg ofcalcium, which is only 20% of the recommended intake for a pregnant woman age 19 or older. The reason it does notcontain more is that the tablet would have to be very largeto provide the recommendation of 1000 mg. To meet herneeds, a pregnant woman would need to consume thistablet plus the amount of calcium in about three glasses of milk. For similar reasons, the tablet doesn’t meet therecommendation for magnesium.

Even if all the calcium and magnesium needed forpregnancy could be packed into a little pill, it still would not provide everything needed in an adequate diet.Prenatal supplements do not contain the protein needed for tissue synthesis or the complex carbohydrates needed forenergy. They lack fiber, which helps prevent constipation,and they do not contain fluid for expanding blood volumeand maintaining normal bowel function. They also don’tcontain other food components such as the phytochemicals

Teratogen A substance that can causebirth defects.�*

Spontaneous abortion or miscarriageInterruption of pregnancy prior to the 7th month.

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that are supplied by a diet rich in whole grains, fruits, andvegetables. Taking a multivitamin and mineral supplementduring pregnancy can be beneficial as long as therecommended dosage is not exceeded and they do not take the place of a carefully planned diet.

Amount RecommendationsNutrient per Tablet for Pregnancy*Vitamin A (�g) 800 770Vitamin D (�g) 10 5

Vitamin E 11–15 15(mg �-tocopherol)

Vitamin C (mg) 80–120 85Folate (�g DFE) 680–1700 600Thiamin (mg) 1.5 1.4Riboflavin (mg) 1.6–3.0 1.4Niacin (mg) 17–20 18Vitamin B6 (mg) 2.6–10 1.9Vitamin B12 (�g) 2.5–12 2.6Biotin (�g) 30 30Pantothenic acid (mg) 7 6Calcium (mg) 200 1000Iron (mg) 60–65 27Magnesium (mg) 100 350Copper (mg) 2–3 1.0Zinc (mg) 25 11

*Values represent recommendations for a pregnant woman 19 to 30years of age during her third trimester.

Deficiencies or excesses of nutrients can cause birth de-fects Consuming a diet that is low in energy or nutrients can affect the develop-ment of the fetus. Maternal malnutrition can cause fetal growth retardation, lowinfant birth weight, birth defects, premature birth, spontaneous abortion, and still-birth. The effect of malnutrition depends on what is missing from the diet and whenduring the pregnancy it occurs. In general, poor nutrition early in pregnancy affectsembryonic development and the potential of the embryo to survive and poor nutri-tion in the latter part of pregnancy affects fetal growth. Vitamin and mineral intake iscrucial early in pregnancy when cell division and differentiation are taking place; mal-formations or death can result if the embryo does not receive adequate nutrients. Afterthe first trimester, low intakes of micronutrients are less likely to cause birth defectsbecause most organs and structures have already formed, but a low-calorie intake willinterfere with fetal growth. Even a mild energy restriction during the last trimester,when the fetus is growing rapidly, can affect birth weight.

Excesses of some nutrients can cause birth defects. For example, excess vitamin Dcan cause mental retardation in the newborn. Too much preformed vitamin A is ofparticular concern because the risk of abnormalities in the offspring increases evenwhen maternal intake is not extremely high. Too much vitamin A early in pregnancyis the most damaging. A UL of 3000 �g per day has been established for pregnantwomen, ages 19 to 50 years.11 Supplements consumed during pregnancy shouldtherefore contain �-carotene, which is not teratogenic.

Food cravings and aversions during pregnancy are usu-ally harmless When you think of food and pregnancy, pickles and ice creammay come to mind, but most women just crave the ice cream. The foods most com-monly craved during pregnancy are ice cream, sweets, candy (especially chocolate),


Zygote formationand implantation

Embryonic or fetal age (weeks) 8 9 383

Embryonic development Fetaldevelopment

Central nervous system

Heart

Extremities

Eyes

Ears

Teeth

External genitalia

Indicates when damage from teratogens is likely to be greatest

Indicates when damage from teratogens may be less severe

F I G U R E 1 2 . 1 0

The critical periods of development vary for different body systems, but for most, exposure to teratogens is most damaging during the embryonic period. (Adapted fromMoore, K., and Persaud, T. The Developing Human, 5th ed. Philadelphia: W. B. Saunders Company, 1993.)


fruit, and fish. Common aversions include coffee and other caffeinated drinks, highlyseasoned foods, or fried foods.13 Why women have these cravings and aversions is stilla matter for debate. It has been suggested that hormonal or physiological changes dur-ing pregnancy—in particular, changes in taste and smell—may be the physiologicalbasis. But there are also psychological and behavioral factors involved.

Usually the things women crave during pregnancy are foods, and generally theyhave no harmful effects and can be consumed within reason. After all, a healthy dietnot only meets your nutritional needs, but also your emotional needs and individualpreferences. But when the things craved, and consumed, are not food, the health con-sequences can be serious. The abnormal craving for and ingestion of nonfood sub-stances having little or no nutritional value is called pica. Women with picacommonly consume clay, laundry starch, ice and freezer frost, baking soda, cornstarch,and ashes. Consuming large amounts of these can reduce the intake of nutrient-densefoods, reduce nutrient absorption from food, increase the risk of consuming toxins,and even cause intestinal obstructions. Complications of pica include iron-deficiencyanemia, lead poisoning, and parasitic infestations.14 Anemia and high blood pressureare more common in mothers who practice pica, but it is not clear if pica is a result ofthese conditions or a cause. In newborns, anemia and low birth weight are often relatedto pica in the mother.

Pica has been described since antiquity but its cause is still a mystery. It was oncethought that pica was an attempt to meet micronutrient needs. It is now believed thatpica may be more related to cultural factors than the need for micronutrients. It ismore common in areas of low socioeconomic status and among women (especiallypregnant women) and children.14

Exposure to environmental toxins can be dangerous In apregnant woman, exposure to toxic substances—such as cleaning solvents, lead, mer-cury, insecticides, and paint—can affect her developing child. Therefore, pregnantwomen need to be aware of the potential toxins in their food, water, and environ-ment. In the case of mercury, exposure can be controlled by avoiding excess consump-tion of fish such as shark, swordfish, king mackerel, or tilefish and by limiting tunaintake to no more than 6 ounces of albacore per week. Up to 12 ounces (about 2meals) a week of varieties of fish and shellfish that are lower in mercury, such asshrimp, canned light tuna, salmon, pollock, and catfish, can be safely consumed.15

Cigarette smoke affects the baby before birth and through-out life If a woman smokes cigarettes during pregnancy, her baby will be affectedbefore birth and throughout life. Compounds in tobacco smoke bind to hemoglobinand reduce oxygen delivery to fetal tissues. The nicotine absorbed from cigarette smokeconstricts arteries and limits blood flow, reducing both oxygen and nutrient delivery tothe fetus. Low birth weight is about 58% more common in offspring of smokers thannonsmokers.16 Even exposure to cigarette smoke from the environment has been foundto increase the risk of low birth weight.17 The risks of miscarriage, stillbirth, and pre-mature birth are also increased in mothers who smoke. The risk of sudden infant deathsyndrome (SIDS, or crib death) and respiratory problems are increased in children ex-posed to cigarette smoke both in the uterus and after birth. The effects of maternalsmoking follow children throughout life; they are more likely to have frequent coldsand develop lung problems later in life.18

Alcohol consumption is a major cause of birth defectsYou wouldn’t serve your baby a glass of wine, yet about 13% of women report drink-ing alcohol during pregnancy.19 Alcohol consumption during pregnancy is one of theleading causes of preventable birth defects. Alcohol is a teratogen that is particularlydamaging to the developing central nervous system.20 It also indirectly affects fetalgrowth and development because it is a toxin that reduces blood flow to the placenta,thereby decreasing the delivery of oxygen and nutrients to the fetus. The consumptionof alcohol can also impair maternal nutritional status, further increasing the risk to theembryo or fetus.

Pica An abnormal craving for andingestion of unusual food and nonfoodsubstances.

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The word pica is Latin for magpie—a bird notorious for eating almostanything.

Coffee is part of our culture, butmany pregnant women limit coffeeintake because they are afraid thecaffeine in coffee will harm theirbaby. Research, however, has foundlittle consistent evidence thatcaffeine consumption increases therisk of any reproductive problem.

Sudden infant death syndrome(SIDS) or crib death The unexplained deathof an infant, usually during sleep.

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Prenatal exposure to alcohol can cause a spectrum of disorders depending on thedose, timing, and duration of the exposure. One of the most severe effects of drinkingduring pregnancy is fetal alcohol syndrome (FAS), which causes facial deformities,growth retardation, and permanent brain damage (Figure 12.11). Newborns with thesyndrome may be shaky and irritable, with poor muscle tone and alcohol withdrawalsymptoms. Other problems include heart and urinary tract defects, impaired visionand hearing, and delayed language development. Mental retardation is the most com-mon and most serious effect. Not all babies exposed to alcohol have FAS, but manyhave some alcohol-related problems. Alcohol-related neurodevelopmental disorders(ARND) are functional or mental impairments linked to prenatal alcohol exposure,and alcohol-related birth defects (ARBD) are malformations in the skeleton or majororgan systems. These conditions are less severe than FAS, but occur about three timesmore often.

Because alcohol consumption in each trimester has been associated with abnormal-ities, and because there is no level of alcohol consumption that is known to be safe,complete abstinence from alcohol is recommended during pregnancy. Warning labelsthat appear on containers of beer, wine, and hard liquor state that “According to theSurgeon General, women should not drink alcoholic beverages during pregnancy be-cause of the risk of birth defects.”

Illegal drugs can affect pregnancy outcome Substance abuseduring pregnancy is a national health issue. Prenatal exposure to cocaine, opiates, oramphetamines has been shown to affect infant behavior and impact learning and at-tention span during childhood.21 It is estimated that from 1 to 11% of babies borneach year have been exposed to drugs during the prenatal period. These numbers in-clude only the use of illicit drugs and would be much larger if alcohol and nicotinewere included.22

Marijuana and cocaine are drugs that are commonly used during pregnancy.Both cross the placenta and enter the fetal blood. There is little evidence that mari-juana affects fetal outcome, but cocaine use increases the risk of complications tothe mother and creates problems for the infant before, during, and after delivery.23

Cocaine is a central nervous system stimulant, but many of its effects during preg-nancy occur because it constricts blood vessels, thereby reducing the flow of oxygenand nutrients to the rapidly dividing fetal cells. Cocaine use during pregnancy is as-sociated with a high rate of miscarriages, intrauterine growth retardation, sponta-neous abortion, premature labor and delivery, low-birth-weight infants, and birth


F I G U R E 1 2 . 1 1

Children with fetal alcohol syndrome have common facial characteristics. The headcircumference is small, the cheekbones are poorly developed, the nose is short with a lownasal bridge between the eyes, the area under the nose is flat, and the upper lip is thin.(George Steinmetz)

Fetal alcohol syndrome A characteristicgroup of physical and mental abnormalitiesin an infant resulting from maternal alcoholconsumption during pregnancy.

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Fetal alcohol syndrome is 100%preventable if a woman does notdrink while she is pregnant. Itoccurs in 0.2 to 1.5 per 1000 livebirths from the general populationand 43 of every 1000 babies bornto heavy drinkers.

For information on thedangers of alcoholconsumption duringpregnancy go to the

National Organization onFetal Alcohol Syndrome at www.nofas.org/


defects.24 Babies exposed to cocaine show signs of withdrawal and abnormalities inarousal, attention, and neurological function, but there is little evidence that theseproblems continue beyond early infancy and childhood.23,24

Complications During Pregnancy Put Mother and Baby at Risk

Most of the 4 million women who give birth every year in the United States arehealthy during pregnancy and produce healthy babies. However, childbearing is notwithout risks. In the United States, 300 to 500 women die yearly as a result of child-birth. Eleven percent of babies are born too soon, 7.4% are low birth weight, and 7.2out of each 1000 born alive die within the first year of life.25 If complications such asdiabetes and hypertension that occur during pregnancy are caught early they can oftenbe managed, allowing for a healthy delivery (Figure 12.12).

Gestational diabetes makes delivery difficult for mother and childDiabetes that develops during pregnancy is known as gestational diabetes. It occursin 2 to 6% of all pregnancies and is most common in obese women.26 It usually disap-pears when the pregnancy is completed, but the mother remains at higher risk for de-veloping type 2 diabetes later on in life (see Chapter 4). In addition to its effects onthe mother’s health, gestational diabetes increases risks for the baby. Because glucosein the mother’s blood passes freely across the placenta, when the mother’s blood levelsare high, the growing fetus receives extra calories. This extra energy promotes growth,resulting in babies who are large for gestational age and consequently at increased riskof complications. As with other types of diabetes, the treatment of gestational diabetesinvolves consuming a carefully planned diet, moderate daily exercise, and in somecases, insulin.

Pregnancy-induced hypertension can be life-threateningPregnancy-induced hypertension is a spectrum of conditions involving elevated bloodpressure that occurs in about 6 to 8% of pregnancies. It is a major risk factor for ma-ternal and fetal illness and death; it accounts for nearly 15% of pregnancy-related ma-ternal deaths in the United States.27 It is more common in mothers under 20 or over35 years of age, those in low-income groups, and women with chronic hypertensionor kidney disease.

The mildest form of pregnancy-induced hypertension is gestational hypertension,which is an abnormal rise in blood pressure that occurs after the 20th week of preg-nancy. If the rise in blood pressure is accompanied by excretion of protein in the urine

F I G U R E 1 2 . 1 2

Prenatal care helps prevent complications duringpregnancy. By monitoring the mother’s bloodpressure as shown here, as well as her blood sugarand the baby’s size and heartbeat, problems can beidentified and treated early. (Faye Norman/SciencePhoto Library/Photo Researchers)

Gestational diabetes A consistentlyelevated blood glucose level that developsduring pregnancy and returns to normalafter delivery.

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Pregnancy-induced hypertensionA spectrum of conditions involving elevatedblood pressure during pregnancy.

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Gestational hypertension High bloodpressure that develops after the 20th week ofpregnancy and returns to normal after delivery.It may be an early sign of preeclampsia.

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and edema the condition is called preeclampsia. Its onset is often signaled by a weightgain of several pounds within a few days. It can progress to a more severe form ofpregnancy-induced hypertension called eclampsia, in which life-threatening seizuresoccur.

The cause of pregnancy-induced hypertension is not known. At one time low-sodium diets were prescribed to prevent preeclampsia but more recent studies havefound reducing sodium intake to be of no benefit.5 Calcium may play a role in pre-venting pregnancy-induced hypertension but the evidence of a connection is notstrong enough to support routine supplementation. Pregnant teens, individuals withinadequate calcium intake, and women known to be at risk of developing pregnancy-induced hypertension may benefit from additional dietary calcium during preg-nancy.28 Treatment includes bed rest and careful medical attention. The conditionusually resolves after delivery.

Nutrition, Income, and Age Can Affect Pregnancy Outcome 421

For information aboutprenatal care, risksand problems duringpregnancy, and

postnatal care, go to theNew York Online Access to Health (NOAH)at www.noah-health.org/ and click on“Pregnancy” under Health Topics.

Preeclampsia A condition characterizedby an increase in body weight, elevated bloodpressure, protein in the urine, and edema. Itcan progress to eclampsia which can be life-threatening to mother and fetus.

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Eclampsia A life-threatening conditionthat can occur during pregnancy. It ischaracterized by high blood pressure,protein in the urine, convulsions, and coma.

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Nutrition, Income, and Age Can Affect Pregnancy Outcome

Some women and their babies are at increased risk for complications because theystart their pregnancy poorly nourished. Others may be at risk because they have lim-ited access to nutritious foods and prenatal care. The mother’s age can also affect thechances of a healthy pregnancy.

Nutritional health is important for conceptionand pregnancy outcomeBeing well nourished before pregnancy is important to support conception and maxi-mize the likelihood of a healthy pregnancy. If a woman is consuming a diet that meetsher needs for energy and all essential nutrients and that is plentiful in whole grains,fruits, and vegetables, it will help ensure that her body is prepared for a pregnancy.Deficiencies or excesses can reduce fertility and affect pregnancy outcome. Starvationdiets, eating disorders, and excessive athletic activity, such as marathon running, caninterfere with ovulation and therefore make conception less likely. Obesity can alterhormone levels and decrease fertility. Excess vitamin A early in pregnancy can causebirth defects and poor folate status can increase the likelihood of birth defects.

The use of certain birth control methods can affect nutritional status, and thesecan therefore have an impact on a subsequent pregnancy. Oral contraceptives maycause a rise in fasting blood sugar and a tendency toward abnormal glucose tolerancein those with a family history of diabetes. They may also cause changes in body com-position, including weight gain due to water retention and an increase in lean bodymass. Oral contraceptives may reduce the need for iron by reducing menstrual flowand increasing iron absorption. Therefore, a special RDA for iron of 11.4 mg per dayhas been established for those taking oral contraceptives (the RDA for menstruatingwomen not using oral contraceptives is 18 mg per day). Blood levels of some B vita-mins have been found to be low in oral contraceptive users, although it is not knownwhether these changes in blood levels reflect an increased need for these nutrients.9

For example, oral contraceptive use is associated with reduced blood levels of vitaminsB6 and B12. If conception occurs soon after oral contraceptive use stops, these levelswill not have had time to return to normal before pregnancy begins.

A woman’s pregnancy history also affects her chances of having a healthy pregnancy.Frequent pregnancies, with little time between, increase the risk for malnutrition be-cause the mother may not have replenished nutrient stores depleted in the first preg-nancy when she becomes pregnant again. A short interval between pregnancies alsoincreases the risk of preterm and low-birth-weight infants. Women with a history ofpoor pregnancy outcome are generally at increased risk. For example, a woman who hashad a number of miscarriages is more likely to have another, and a woman who has hadone child with a birth defect has an increased risk for defects in subsequent children.


Poverty increases the risks of pregnancyOne of the greatest risk factors for poor pregnancy outcome is low-income level.Poverty limits access to food, education, and health care.29 Low-income women have ahigher incidence of low-birth-weight and preterm infants. Low-income women areunlikely to receive any prenatal care until late in pregnancy. One federally funded pro-gram that addresses the nutritional needs of pregnant women is the Special Supple-mental Nutrition Program for Women, Infants, and Children (WIC). WIC hasbeen shown to reduce health-care costs by providing preventive care to low-incomepregnant women through nutrition education and food vouchers. This programprovides services to pregnant women, to nonlactating women for 6 months afterbirth, to lactating women for 12 months after birth, and to infants and children upto 5 years of age, but it does not address the need for good nutrition for womenplanning a pregnancy.

Pregnant teenagers face economic, social,medical, and nutritional problemsPregnancy places a stress on the body at any age, but this is compounded when themother herself is still growing. Although the rate of teen pregnancy has been decreas-ing over the past decade, from 62.1 babies per 1000 teens in 1991, to 48.5 per 1000in 2001, it remains a major public health problem.30 Pregnant teens are at greater riskof pregnancy-induced hypertension and are more likely to deliver preterm and low-birth-weight babies. To produce a healthy baby, a pregnant teenager needs early med-ical intervention and nutritional counseling.

Adolescent girls continue to grow and mature physically for about 4 to 7 years aftermenstruation begins. Therefore the diet of a pregnant teen must provide both for hergrowth and that of her baby. Because the nutrient needs of a pregnant teen may behigher than those of a pregnant adult, the DRIs include a special set of nutrient rec-ommendations for pregnant teens (Figure 12.13). Consuming a diet that meets theseneeds can be challenging. Even nonpregnant teens often fall short of meeting theirnutrient needs. Nutrients that are commonly low in the diets of pregnant teens arecalcium, iron, zinc, magnesium, vitamin D, folate, and vitamin B6.

6,9,11

Riboflavin

Niacin

Vitamin B6

Folate

Vitamin B12

Calcium

Magnesium

Iron

Zinc

Iodine

Chromium

Copper

Selenium

Percent increase0 20 40 60 80 100

Vitamin A

Vitamin D

Vitamin E

Vitamin K

Vitamin C

Thiamin

For information aboutprograms such as WICthat are designed toimprove the nutrition of

women and children, goto the USDA Food and Nutrition

Service at www.fns.usda.gov/fns/

F I G U R E 1 2 . 1 3

The need for many micronutrients increasesduring pregnancy. The percentage increases inmicronutrient needs above nonpregnant levelsare shown here for a 14- to 18-year-old teenduring pregnancy.

Older mothers are more likely to beginpregnancy with health problemsThe nutritional requirements for older women during pregnancy are no different thanfor women in their 20’s, but pregnancy after the age of 35 does carry additional risksbecause older women are more likely to start pregnancy with health problems such ascardiovascular disease, kidney disorders, obesity, and diabetes.31 During pregnancy,older women are more likely to develop gestational diabetes, pregnancy-induced hy-pertension, and other complications. They also have a higher incidence of low-birth-weight deliveries and of chromosomal abnormalities, especially Down syndrome.Today, careful medical monitoring throughout pregnancy is reducing the risks toolder mothers and their babies (Figure 12.14).

Medications used to treat existing illness can also affect nutritional status and con-sequently both fertility and pregnancy outcome. A woman who is considering preg-nancy should discuss her plans with her physician in order to determine the risksassociated with any medication she is taking.

Nutrition, Income, and Age Can Affect Pregnancy Outcome 423

So, What Should I Eat?

Make nutrient-dense choices to meet the extra nutrient needs of pregnancy• Have yogurt for a mid-morning snack• Put some peanut butter on your banana to add some protein to your snack• Have a plate of pasta—it’s fortified with folic acid

Drink plenty of fluids• Have a glass of milk and get calcium with your fluids• Keep a bottle of water at your desk or in your car• Relax with a cup of tea

Indulge your cravings, within reason• That bowl of ice cream does add calcium and protein• Enjoy your cookies, with a glass of milk

F I G U R E 1 2 . 1 4

Prenatal care with careful medical monitoring canhelp older women have uncomplicated pregnanciesand produce healthy babies. (Steward Cohen/Stone/Getty Images)

Down syndrome A disorder caused by extra genetic material that results indistinctive facial characteristics, mentalretardation, and other abnormalities.

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The need for many nutrients is even greater during lactation than during pregnancy.This is because the milk produced by a breast-feeding mother must meet all the nutri-ent needs of her baby, who is growing rapidly and is larger and more active than thefetus. To meet these needs, a lactating woman must choose a varied nutrient-densediet that follows the Food Guide Pyramid recommendations for lactating women (seeFigure 12.8). Most lactating women can meet all their needs without supplements.

Milk production varies to meet the demandsof the infantThe production of human milk is stimulated by the infant’s suckling; suckling causesthe release of the pituitary hormone prolactin, which stimulates milk production. Therelease of milk from the milk-producing glands and its movement through the ductsand storage sinuses is referred to as let-down (Figure 12.15). The let-down of milk iscaused by oxytocin, another hormone produced by the pituitary gland. Oxytocin re-lease is also stimulated by the suckling of the infant, but as nursing becomes more au-tomatic, oxytocin release and the let-down of milk may occur in response to the sightor sound of an infant. It can be inhibited by nervous tension, fatigue, or embarrass-ment. The let-down response is essential for successful breast-feeding and makes suck-ling easier for the child. If let-down is slow, the child can become frustrated anddifficult to feed.

The more the infant suckles, the more milk is produced. During the first 6 monthsof lactation, approximately 600 to 900 ml, or 2.5 to 3.75 cups, of milk is produceddaily. The amount is increased or decreased depending on the amount that the infantconsumes. Human milk contains about 160 Calories per cup (240 ml). Providing aninfant with 3 cups of milk would require approximately 500 Calories from themother. Her intake must support milk production and can influence the nutrientcomposition of her milk.

Nutritional Needs Are Greater During Lactation than Pregnancy

Milk-producinggland

Duct

Adiposetissue

NippleMilk storagesinus

F I G U R E 1 2 . 1 5

During lactation, milk travels from the milk-producing glandsthrough the ducts to milk storage sinuses and then to the nipple.

Let-down A hormonal reflex triggeredby the infant’s suckling that causes milk tobe released from the milk glands and flowthrough the duct system to the nipple.

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Energy and protein needs are increasedduring lactationSome of the calories needed to produce breast milk come from the mother’s fat storesand some come from her diet.4 An additional 330 Calories per day are recommendedabove nonpregnant needs during the first 6 months of lactation, and 400 Calories perday during the second 6 months (see Figure 12.7). To ensure adequate protein formilk production, the RDA for lactation is increased by 25 grams per day. The RDAfor carbohydrate and the AIs for the essential fatty acids linoleic and �-linolenic acidare also higher during lactation (see inside cover).4

The mobilization of body fat to meet the needs of milk production may help pro-mote weight loss after pregnancy. Beginning 1 month after birth, most lactatingwomen lose 0.5 to 1 kilogram (1 to 2 pounds) per month for 6 months. Some womenwill lose more, and others may maintain or even gain weight regardless of whether ornot they breast feed. Rapid weight loss is not recommended during lactation becauseit can decrease milk production; regular exercise may speed weight loss and does notimpair milk production.

Lactating women need more fluidsThe amount of milk a woman produces depends on how much her baby demands. Toavoid dehydration and ensure adequate milk production, lactating women need toconsume about 1 liter of additional fluid per day. The AI of 3.8 liters per day, ofwhich about 3.1 liters is from drinking water and other beverages, is based on typicalintake during lactation.5 Consuming an extra glass of milk, juice, or water at everymeal and whenever the infant nurses can help ensure adequate fluid intake.

Vitamin and mineral needs are increasedduring lactationThe recommended intakes for several vitamins and minerals are increased during lac-tation to meet the needs for synthesizing milk and to replace the nutrients secreted inthe milk itself (see Figure 12.7). Maternal intake of some vitamins including vitaminsC, B6, B12, A, and D can affect milk composition. The recommended intakes of vita-min B6, B12, other B vitamins, and vitamins A, C, and E are increased above nonlac-tating levels. Because vitamin B12 may be deficient in the breast milk of veganmothers, their infants should be supplemented with vitamin B12.

For other nutrients, including calcium and folate, levels in the milk are maintainedat the expense of maternal stores. Much of the calcium secreted in human milk comesfrom the mother’s bones. The AI for calcium is not increased above nonlactating levelsbecause the loss of calcium from maternal bones is not prevented by increases in di-etary calcium. Calcium supplements during lactation also do not affect the concentra-tion of calcium in the milk or the minerals in the mother’s bones.32 The calcium lostfrom bones is restored after weaning. Folate needs are increased to account for theamount secreted in milk.9 Iron needs are not increased during lactation because littleiron is lost in milk, and, in most women, losses are decreased because menstruationstops. The RDA for lactation is 9 mg per day, half that of nonlactating women.11

An Infant’s Intake Must Provide for Growth, Development, and Activity 425

An Infant’s Intake Must Provide for Growth,Development, and Activity

When a child is born and the umbilical cord is cut, he or she suddenly becomes ac-tively involved in obtaining nutrients rather than being passively fed through the pla-centa (Figure 12.16). The energy and nutrients the infant consumes must support hisor her continuing growth and development, as well as an increasing level of activity.


Infants’ energy intake must provide for their rapid growthGrowth during the first few months after birth is more rapid than at any other time.Therefore, infants need more calories per pound of body weight than at any othertime of life.4 Differences in growth rates are reflected in the separate EER predictionequations for infants 0 to 3 months, 4 to 6 months, and 7 to 12 months (see insidecover). The calories needed for activity also increase as the child becomes more mobileand active.

Infants need a higher proportion of their calories from fatHealthy infants consume about 55% of their energy as fat during the first 6 months oflife, and 40% during the second 6 months. This is far greater than the 20 to 35% ofcalories from fat recommended in the adult diet (Figure 12.17). This energy-densediet allows the infant’s small stomach to hold enough food to meet energy needs. Car-bohydrate is also a major contributor to energy intake in the infant; most of this isfrom lactose. As the infant grows and solid foods are introduced into the diet, the per-centage of calories from carbohydrate in the diet increases and the percentage from fatdecreases.

In addition to getting enough fat to meet energy needs, infants need the rightkinds of fat. A sufficient supply of the omega-3 fatty acid DHA and the omega-6 fattyacid arachidonic acid are important for nervous system development. These fatty acidsare constituents of cell membranes and are incorporated into brain tissue and theretina of the eye. Breast milk is high in these fats and infant formulas are designed tomimic the composition of breast milk. AIs for infants have been set for total omega-3and total omega-6 fatty acids based on the amounts of these types of fatty acids inhuman milk (see inside cover).4

Infants require almost twice as much protein per kilogram as adultsInfants’ protein requirements per unit of body weight are very high compared withthe adult requirement: The AI from birth to 6 months of age is 1.52 grams per kilo-gram, compared with 0.8 grams per kilogram for an adult. Human milk is the idealprotein source for newborns; its amino acid pattern matches their needs. Infant for-mulas are manufactured to mimic this amino acid pattern. Despite the importance ofprotein for growing infants, too much can also be detrimental. The excess protein isbroken down and the nitrogen wastes must be excreted in the urine. This increase inwastes increases water loss in urine and can lead to dehydration.

F I G U R E 1 2 . 1 6

At birth the umbilical cord is cut, so the childmust now obtain nutrients by mouth. (TomGalliher/Corbis Images)

40%Carbohydrate

45–65%Carbohydrate

54%Fat

20–35%Fat

6%Protein

10–35%Protein

Calorie distribution infantsget from human milk

Recommended calorie distributionfor adults

Compared to an adult, an infantneeds far more calories per pound.For example, a 30-year-old adultman who is 5 feet 10 inches talland weighs 170 pounds needsabout 18 Calories per pound. A 5-month-old baby boy needs about38 Calories per pound. If an adultburned this many Calories perpound this 170-pound man wouldneed to eat 6460 Calories a day!

F I G U R E 1 2 . 1 7

Comparing the proportion of calories from carbohydrate, fat, and proteinin human milk to the proportions recommended for adults shows howmuch more fat is needed by infants.

In the developing world, diarrhea isthe most common cause of infantdeath, and in the United States it kills one child each day. Thecause of the diarrhea is usually a bacterial or viral infection; thecause of death is dehydration. Thefluid intake of infants with diarrheashould be monitored carefully,and a pediatrician should becontacted. Mixtures of sugar,water, and electrolytes areavailable to replace lost fluids.

Infants lose more water in urine and through evaporation than adultsWater balance is different in infants than in children and adults. They have a higherproportion of body water and they lose proportionately more water in urine andthrough evaporation than adults. Urine losses are high because the infant kidneys arepoorly developed and unable to reabsorb much of the water that passes through them.They lose proportionately more water through evaporation because they have a largesurface area compared with their total body weight. These factors, in addition to thefact that infants cannot tell us they are thirsty, put them at risk for dehydration. De-spite high water losses infants who are exclusively breast-fed do not require additionalwater. The AI is based on the volume of human milk consumed and the water contentof the milk. It is set at 0.7 liters per day for infants 0 to 6 months and at 0.8 liters perday for older infants (7 to 12 months).5 In older infants some fluid is obtained fromother beverages and foods. Although breast milk can meet fluid needs in healthy in-fants, when water losses are increased by diarrhea or vomiting additional fluids may beneeded.

Iron stores help meet needs for the first 4 months of lifeIron is the nutrient most commonly deficient in infants who are consuming adequateenergy and protein. Iron deficiency is usually not a problem during the first 4 to 6months of life because infants have iron stores at birth and the iron in human milk,though not particularly abundant, is very well absorbed. About 50% of the iron inhuman milk is absorbed, compared with only 2 to 30% from many other foods. TheAI for iron from birth to 6 months is only 0.27 mg per day. After 4 to 6 months, ironstores are depleted but iron needs remain high. The RDA for infants 7 to 12 monthsincreases to 11 mg per day.11 By this age the diets of breast-fed infants should containother sources of iron, such as iron-fortified rice cereal. Formula-fed infants should befed iron-fortified formula.

Vitamin D deficiency is a concern if sun exposure is lowNewborns are potentially at risk for vitamin D deficiency. Breast milk is relatively lowin vitamin D, so breast-fed infants who do not receive adequate exposure to sunlight,such as those living in cold climates, may not obtain adequate vitamin D. To synthe-size adequate vitamin D, about 15 minutes per day of sun exposure, with only the faceexposed, is needed for light-skinned babies; a longer time is required for darker-skinned babies (Figure 12.18).

An AI of 5 �g of vitamin D has been set for infants 0 to 12 months of age.6 Thismay be provided as a supplement for breast-fed infants. Infant formulas contain 10�g of vitamin D per liter of formula.

Vitamin K injections are given at birthInfants are at risk for vitamin K deficiency for a number of reasons. Little of this vi-tamin crosses the placenta from mother to fetus. At birth the infant’s gut is sterile sono microbial vitamin K synthesis occurs. In addition, breast milk is low in vitaminK. Since vitamin K is needed for blood clotting, breast-fed infants are at risk of hem-orrhage due to vitamin K deficiency. To prevent the possibility of hemorrhage most newborns receive a vitamin K injection at birth. This provides them withenough vitamin K to last until their intestines are colonized with the bacteria thatsynthesize it.

An Infant’s Intake Must Provide for Growth, Development, and Activity 427

F I G U R E 1 2 . 1 8

Dark skin pigmentation reduces the amountof vitamin D synthesized during the time a baby is outdoors. Babies with dark skin are therefore at greater risk of vitamin Ddeficiency. (© ROB & SAS/Corbis Images)


Fluoride supplements are needed if the localwater supply is low in fluorideBabies have no teeth, but they still need fluoride because it is important for tooth de-velopment before they erupt. Breast milk is low in fluoride, and formula manufactur-ers use unfluoridated water in preparing liquid formula. Therefore, breast-fed infants,infants fed premixed formula, and those fed formula mixed with low-fluoride waterare often supplemented beginning at 6 months of age. In areas where the drinkingwater is fluoridated, infants fed formula reconstituted with tap water should not begiven fluoride supplements.

Growth is the best indicator of adequatenourishmentAlthough nutrient needs for infants are fairly well defined, it is difficult to calculate aninfant’s actual nutrient intake—particularly if they are breast-feeding. Therefore, thebest way to tell if they are receiving adequate nourishment is to monitor their growth.Breast-fed and bottle-fed infants have similar growth rates for the first 3 to 4 months,but then bottle-fed infants grow at a faster rate. Whether an infant is 6 pounds or 8pounds at birth, the rate of growth should be approximately the same—rapid initiallyand slowing slightly as the infant approaches 1 year of age. A rule of thumb is that aninfant’s birth weight should double by 4 months and triple by 1 year of age. In thefirst year of life, most infants increase their length by 50%.

Growth charts are used to monitor growth Because mosthealthy infants follow standard patterns of growth, growth charts can be used to com-pare their length, weight, and head circumference measures to those of infants of thesame age (see Appendix B; Figure 12.19).33 To account for the variability of growthpatterns among ethnic groups and breast-fed and bottle-fed babies, these charts aredeveloped using data from all segments of the U.S. population. For infants, charts areavailable to monitor weight-for-age, length-for-age, and head-circumference-for-age.The resulting ranking, or percentile, indicates where the infant’s growth falls in rela-tion to population standards. For example, if a newborn boy is at the 20th percentilefor weight, it means that 19% of newborn boys weigh less and 80% weigh more.Children usually continue at the same percentiles as they grow. For instance, a childwho is at the 50th percentile for height and 25th percentile for weight should con-tinue to follow approximately these height and weight curves. Small infants and pre-mature infants often follow a pattern parallel to but below the growth curve for aperiod of time and then experience catch-up growth that brings them onto the growthcurve in a place compatible with their genetic growth potential.

Dramatic changes in growth rate suggest malnutritionSlight fluctuations in growth rate are normal, but a consistent pattern of not followingthe growth curve or a sudden change in growth pattern is cause for concern and couldindicate overnutrition or undernutrition. A rapid increase in weight without an in-crease in height may be an indicator that the infant is being overfed. Because over-weight children grow into overweight adults, this pattern of weight increase should beaddressed early in life.

Growth that is slower than the predicted pattern indicates failure to thrive. This isa catch-all term for any type of growth failure in a young child. The cause may be acongenital condition, the presence of disease, poor nutrition, neglect, abuse, or psy-chosocial problems. The treatment is usually an individualized plan that includes ade-quate nutrition and careful monitoring by physicians, dietitians, and other health-careprofessionals. Just as there are critical periods in fetal life, there are critical periods forgrowth and development during infancy when undernutrition can have permanenteffects.

If you use bottled water to mixinfant formula, the baby will not begetting fluoride. Only a few bottledwaters contain fluoride.

Failure to thrive The inability of achild’s growth to keep up with normalgrowth curves.

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Infant Nutrient Needs Can Be Met by Breast Milk or Formula

Infant Nutrient Needs Can Be Met by Breast Milk or Formula 429

Age (months)3 6 9 12 15 18 21 24 27 30 33 36Birth

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

4

6

8

10

12

14

16

18

20

22

24

26

28

30

32

34

36

38

40

CDC Growth Charts: United States

4

6

8

10

12

14

16

18

20

22

24

26

28

30

32

34

36

38

40

Weight-for-age percentiles:Boys, birth to 36 months

97th

10th

95th

90th

75th

50th

25th

10th5th

3rd

kg lb

kg lb

lb

lb

SOURCE: Developed by the National Center for Health Statistics in collaboration with

the Nation Center for Chronic Disease Prevention and Health Promotion (2000).CDC

CENTER FOR DISEASE CONTROLAND PREVENTION

F I G U R E 1 2 . 1 9

Growth charts, such as this one, which showsweight-for-age percentiles for boys from birthto 36 months of age, demonstrate typicalpatterns of growth. The blue line follows thepattern of growth for an infant whose birthweight was at the 40th percentile andcontinued to grow along this curve.

From birth until 4 to 6 months of age infants do not need anything other than breastmilk or formula to meet their nutrient needs. A strong, healthy baby will be able tosuckle shortly after birth. Newborn infants have small stomachs and high nutrientneeds. Therefore, to receive adequate nutrients, whether fed from the breast or bottle,young infants should be fed frequently on demand, about every 1.5 to 3 hours. Forbreast-fed infants, a feeding should last approximately 8 to 12 minutes at each breast(Figure 12.20). When bottle-feeding, infants should be held alternately between theleft and right arms to promote equal development of the head and neck muscles (Fig-ure 12.21). Bottle-fed newborns may consume only a few ounces of formula at eachfeeding; as the infant grows, the amount consumed at each feeding will increase to 4to 8 ounces. Caregivers should respond to cues from the infant that hunger is satisfied,even if a bottle of formula is not finished. Encouraging infants to finish every bottlecan result in overfeeding and excess weight gain. Breast-fed babies are unlikely to beoverfed, because the amount of milk consumed cannot be monitored visually. A well-fed


newborn, whether breast- or bottle-fed, should urinate enough to soak six to eightdiapers a day and gain about 1/3 to 1/2 pound per week.

Infants should never be put to bed with a bottle. While the child sleeps, the flow ofsaliva is decreased and the sugary liquid formula remains in contact with the teeth formany hours. This causes the rapid and serious decay of the upper teeth referred to asnursing bottle syndrome. Usually, the lower teeth are protected by the tongue and areunaffected (Figure 12.22).

Breast-feeding has health and nutritionaladvantages for mother and childPsychologically, breast-feeding can be a relaxing, emotionally enjoyable interaction forboth mother and infant (Table 12.2). Because of its health and nutritional benefits itis the recommended choice for feeding the newborn of a healthy, well-nourishedmother. Even babies who are too small or weak to receive adequate nutrition by suck-ling at the breast can be fed breast milk offered in a bottle.

Breast-feeding helps mothers recover and keeps babieshealthy For the mother, breast-feeding causes uterine contractions that help heruterus return to size more quickly. It may promote weight loss in some women, espe-cially when continued for more than 6 months.34 Women who breast feed may have alower risk of developing osteoporosis and breast and ovarian cancer. Breast-feedingalso inhibits ovulation, lengthening the time between pregnancies; however, because itdoes not always prevent ovulation, breast-feeding cannot be relied upon for birthcontrol.34

Human milk contains a number of substances that protect infants from disease.Antibody proteins and immune system cells pass from the mother into her milk toprovide the infant immune protection. A number of enzymes and other proteins pre-vent the growth of harmful microorganisms. Several carbohydrates have been identi-fied that protect against disease-causing organisms, including viruses that causediarrhea. One substance favors the growth of the beneficial bacterium Lactobacillusbifidus in the infant’s colon, which inhibits the growth of disease-causing organisms.

F I G U R E 1 2 . 2 0

By the time the infant is 1 week old, mother and child haveusually adjusted to breast-feeding. (Richard Lord/The ImageWorks)

F I G U R E 1 2 . 2 1

During bottle-feeding, the position of the babyand the bottle are both important.The infant’shead should be higher than the stomach, andthe bottle should be tilted so that there is no airin the nipple (Erika Stone/Photo Researchers)

F I G U R E 1 2 . 2 2

Nursing bottle syndrome causes rapid decayof the upper front teeth. (K. L. Boyd, D.D.S./Custom Medical Stock Photo, Inc.)

Nursing bottle syndrome Extremetooth decay in the upper teeth resultingfrom putting a child to bed with a bottlecontaining milk or other sweetened liquids.

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Oral contraceptives can be usedimmediately after pregnancy. Becausethose containing estrogen maydecrease milk volume, formulationscontaining only progestin arepreferable for lactating women.

Breast-fed babies have fewer allergies, ear infections, respiratory illnesses, and urinarytract infections than formula-fed babies, and are less likely to suffer from constipationand diarrhea. There is also evidence that breast-feeding protects against sudden infantdeath syndrome, diabetes, and chronic digestive diseases. In addition to providing dis-ease protection, the strong suckling required for breast-feeding aids in the develop-ment of facial muscles, which help in speech development and the correct formationof teeth.


T A B L E 1 2 . 2Advantages and Disadvantages of Breast- and Bottle-Feeding

Advantage/Disadvantage Breast-Feeding Bottle-Feeding

Nutrients Ideal food for human babies. Modeled after human milk, but certain Composition changes as they components cannot be duplicated. eat and grow. Composition does not change with time.

Must be prepared carefully to supplythe correct nutrient mix and ratio ofnutrients to fluid.

Amount Underfeeding can be a problem in Overfeeding is a risk because of the newborns if the mother is not well desire of caregivers to have the baby versed in breast-feeding and the signs empty the bottle.of dehydration in the infant.

Immunity Immune factors are transferred There are no immune factors in formula.from mother to infant.

Allergies Allergies to breast milk are very rare There are a variety of choices if the and the risk of food allergies is reduced. infant is allergic to one type of formula.

Risk from mother Certain contaminants such as None.environmental pollutants, medications, illicit drugs, and disease-causing organisms such as HIV can pass from mother to baby.

Environmental contamination Breast milk is sterile, but pumped milk Bacterial contamination is a risk if can become contaminated if stored formula is prepared under unsanitary improperly. conditions or stored improperly.

Ease for caregivers No equipment to wash, always Requires more preparation and available, but may require more washing, but other family members time from the mother. can share responsibility for feeding.

Ease for baby Suckling is harder for the baby but aids Easier for baby, which is especially in development of teeth and facial important for weak or sick infants.muscles needed for speech. Weak or sick infants can easily consume pumped breast milk.

Benefit to mother Promotes uterine contractions, which May allow more sleep.help the uterus return to prepregnancy size. May promote loss of weight and body fat if continued for more than 6 months. May reduce risk of breast cancer.

Cost Cheaper, but the mother must More expensive than nursing and be well nourished. includes cost of formula as well as

equipment and energy used inpreparation.


Your Choice: Breast versusBottle—What’s Best for You and Your Baby?

A hundred and fifty years ago the only way to feed a babywas at the breast. A baby who could not be breast-fed hadlittle chance of survival. Today, infants who cannot breastfeed can still thrive and women who cannot or choose notto breast-feed can raise healthy infants. Breast-feeding isstill recommended for healthy mothers and babies becauseof the nutritional and health advantages it offers, butcommercial infant formulas modeled after breast milk havegiven mothers another option. When choosing betweenbreast and bottle nutrition is not the only consideration;ease, convenience, cost, and safety are also important issuesfor many women.

Once established, breast-feeding provides a relaxingbonding experience for mother and child but breast-feedingdoesn’t always come easily to either mother or baby.Difficulty establishing breast-feeding along with sorenipples and engorged breasts may cause some women toturn to bottles. It can also be easier for the infant, becauseless effort is required to bottle feed. However, if the hole in the nipple is too large, the infant may feel full beforereceiving adequate nutrition. If the hole is too small, theinfant may tire before nutrient needs are met.

If cost and the time needed for preparation and clean up is a concern, breast-feeding is the best choice. It is lessexpensive and requires no preparation or bottles andnipples that must be washed. Infant formula can bepurchased in ready-to-feed, liquid concentrate, or powderedforms. The nutritional composition of the formula is not a factor in the choice because the FDA regulates thecomposition and safety of infant formulas. Ready-to-feedformulas are easiest to use but may cost more and areheavier and bulkier to carry home from the store. Liquidconcentrates are a good compromise because they providemore formula for less weight and are easy to mix. Powdersare the least expensive and the easiest to transport home ina grocery bag but require more measuring and mixing. Thecost of even the least expensive formulas, however, is highcompared to the cost of the extra food needed to nourish a lactating mother.

The possibility of contamination and mixing errors is aconcern for bottle-feeding. Breast milk from a healthymother has the correct mix of nutrients and fluid and is freeof microbial contamination. Formula, when it is broughthome from the store, is also free of contamination, but inorder to stay safe and meet nutrient needs, infant formulamust be prepared carefully. If the proper measurements arenot used, the child can get too much or too little of thenutrients and fluid he or she needs. If the water and all theequipment used in preparing formula are not clean or if the

prepared formula is left unrefrigerated, food-borne illnessmay result. To avoid introducing harmful microorganisms,the water used to mix powdered formula should be boiledfor 1 to 2 minutes and allowed to cool before mixing. Handsshould be washed before preparing formula, and bottlesand nipples should be washed in a dishwasher or placed in a pan of boiling water for 5 minutes. Formula should beprepared immediately before a feeding, and any excessshould be discarded. Opened cans of ready-to-feed andliquid concentrate formula should be covered andrefrigerated and used within the time indicated on the can.

The time required of the mother is a major considerationin choosing bottle versus breast. With bottle-feeding,caregivers other than the mother can feed the baby. This isalso possible with milk pumped from the breast and storedfor later feedings. Since pumped milk is exposed to pumpsand bottles, it must be handled with care to avoidcontamination. Pumped milk can be kept refrigerated for 24 to 48 hours, but if it will not be used within that period itshould be frozen in a clean container.

Breast-feeding becomes a disadvantage if there areharmful substances that can be passed from mother to thebaby in her milk. Caffeine in the mother’s diet can make the infant jittery and excitable. Alcohol consumed by themother passes into breast milk and can be harmful to theinfant. Some medications can also pass into breast milk. If a breast-feeding mother needs to take a prescriptionmedication that could harm her baby, she can use a breastpump to maintain milk production but discard the milk until the medication is no longer needed.

When possible breast-feeding is still best, but evenwomen who choose to breast-feed initially may do so foronly a short time. As a result these women will also need to make decisions about formula and bottle-feeding.Ultimately the mother must choose whether breast- orbottle-feeding best meets her needs and those of her infant.

(Charles D. Winters)

Warming breast milk in a microwaveis not recommended because itdestroys some of its immuneproperties. Also, some portions ofthe milk may become dangerouslyhot. The best way to warm milk is byrunning warm water over the bottle.


Breast milk provides the ideal mix of nutrients for younginfants The types and amounts of fat, protein, and carbohydrate in breast milkprovide just what babies need. The fat in human milk is easily digested. It is high incholesterol and the essential fatty acid linoleic acid. It is also high in arachidonic andDHA, fatty acids that are essential for normal brain development, eyesight, andgrowth. Lactalbumin, the predominant protein in human milk, forms a soft, easily di-gested curd in the infant’s stomach. Lactose, the primary carbohydrate in humanmilk, is digested slowly, so it stimulates the growth of acid-producing bacteria. Breastmilk is low in sodium and the zinc, iron, and calcium are present in forms that areeasily absorbed.35

The composition of human milk changes to meet infantneeds The nutrient composition of breast milk changes as the infant develops. Thefirst fluid that is produced by the breast after delivery is called colostrum. Not actuallymilk, colostrum is a yellowish fluid that is higher in water, protein, immune factors,minerals, and some vitamins than milk. It is produced for up to a week after delivery.Colostrum has beneficial effects on the gastrointestinal tract, acting as a laxative thathelps the baby excrete the thick, mucousy stool produced during life in the womb.While colostrum is produced, it may seem that the newborn is not receiving enoughto eat; however, supplemental bottle feedings are not necessary. The nutrients incolostrum meet infant needs until mature milk production begins.

The composition of mature human milk changes over time, meeting the nutrientneeds of the child for up to the first year of life. The fat content of breast milk changesthroughout each feeding, gradually increasing after the first few minutes of each nurs-ing session. Thus, to meet calorie needs it is important for nursing to continue longenough for the infant to obtain the higher-fat milk.

Breast-feeding should be continued for a year or moreBreast-feeding alone can support optimal growth for about 6 months. After 6 months,the American Academy of Pediatrics recommends breast milk along with supplemen-tal feeding of solids for the first year of life—and longer—as mutually desired bymother and child. The World Health Organization recommends that infants in devel-oping nations be breast-fed for 2 years.36 After 12 months, the baby no longer needsformula or breast milk to meet nutrient needs. However, breast-feeding beyond 12months continues to provide nutrition, comfort, and an emotional bond betweenmother and child. As the infant obtains more and more of its energy from solid foods,milk production decreases due to reduced demand by the infant, but physiologically,lactation can continue as long as suckling is maintained.

Infant formulas mimic the composition of human milkInfant formulas can never duplicate the living cells, active hormones, enzymes, andimmune system molecules in human milk, but formulas today try to replicate humanmilk as closely as possible in order to match the growth, nutrient absorption, andother parameters obtained with breast-feeding. Most formula is made from modifiedcow’s milk. For infants who cannot tolerate milk proteins, soy protein formulas areavailable. For those who cannot tolerate soy protein, formulas made from predigestedproteins, called protein hydrolysates, are an option. Special formulas are available forpremature infants and those with genetic abnormalities that alter dietary needs.

Special formulas are available for special needs Prematureinfants have special needs because they do not have fully developed organ systems ormetabolic pathways. If they are too small or weak to nurse or take a bottle, pumpedbreast milk or formula can be fed through a tube. Some nutrients that are produced inthe bodies of full-term infants are essential in the diets of premature infants. For ex-ample, preterm infants are less able to synthesize the amino acids tyrosine and cysteineand the fatty acid DHA. These and other substances, such as taurine and carnitine,

Did you ever hear a baby describedas colicky? Colic involves dailyperiods of inconsolable crying thatcannot be stopped by holding,feeding, or changing the infant.Colic usually begins at a few weeksof age and continues through thefirst 2 to 3 months. It occurs inboth breast- and bottle-fed infantsand its cause is still unknown.Some think colic is related tointestinal gas while others believeit is due to immaturity of thecentral nervous system.

The first commercially sold infantformula had its origins in 1867, whenHenri Nestlé created a mixture ofmilk and cereal that could be used bymothers who were unable to breast-feed. Nestlé began selling the productsoon after it successfully saved thelife of a premature infant.

Colostrum The first milk, which issecreted in late pregnancy and up to aweek after birth. It is rich in protein andimmune factors.

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are needed in higher amounts by premature babies. The energy, protein, and micronu-trient requirements of preterm infants are also higher due to their rapid growth anddevelopment. Preterm breast milk is higher in these substances and infant formulascontaining these are available to meet the needs of premature babies.

Some genetic abnormalities prevent the normal metabolism of specific nutrients.Infants who suffer from these may have altered dietary needs. For instance, infantswith the genetic disease phenylketonuria (PKU) lack an enzyme needed to metabolizethe amino acid phenylalanine (see Chapter 6). If a child with PKU is fed breast milkor regular formula, the by-products of phenylalanine metabolism accumulate and cancause brain damage. This can be prevented by feeding infants with PKU a special for-mula that provides only enough phenylalanine to meet the need for protein synthesis.Because this special diet must be started as soon as possible, infants born in the UnitedStates and Canada are tested for PKU at birth.

There are some situations when bottle feeding is betterBreast milk may be the ideal food for the newborn, but in some cases formula ishealthier. Although common illnesses such as colds, flu, and skin infections are notpassed to the infant in breast milk, some diseases, such as hepatitis and HIV infection,which causes AIDS, can be transmitted to the infant in breast milk.37 Some drugs canalso pass from mother to baby in breast milk. Women who are taking medicationsshould check with their physician as to whether it is safe to breast feed. Because alco-hol and drugs such as cocaine and marijuana can be passed to the baby in breast milk,alcoholic and drug-addicted mothers are counseled not to breast feed. Nicotine fromcigarette smoke is also rapidly transferred from maternal blood to milk, and heavysmoking may decrease the supply of milk.

In the United States, women whoare infected with HIV are advisednot to breast feed, but in developingnations, the risk of malnutritionassociated with not breast-feedingoutweighs the risk of passing thisinfection on to the infant.

Breast-feeding is the bestchoice for a healthy motherand baby, but unfortunatelynot all babies or mothers arehealthy. If the baby has specialneeds or the mother is ill or ondrugs or medication, bottle-feeding may be best.

Solid Food Can Be Introduced Between 4 and 6 Months of Age

Although most of the infant’s nutritional needs are still met by breast milk or formulauntil 1 year of age, solid and semisolid foods can be gradually introduced into the dietstarting between the 4th and 6th months of life. By this time the infant’s feeding abili-ties and gastrointestinal tract are mature enough to handle solid foods. Since theyoung infant takes milk by a licking motion of the tongue called suckling, whichstrokes or milks the liquid from the nipple, solid food placed in the mouth at an earlyage is usually pushed out as the tongue thrusts forward. By 4 to 6 months of age, how-ever, the early reflex to bring the tongue to the front of the mouth to suckle has di-minished and the tongue is held farther back, allowing solid food to be acceptedwithout being expelled. By this age, the infant also can hold his or her head upsteadily and is able to sit, either with or without support. Internally, the digestive tracthas developed, and enzymes are present for starch digestion. The kidneys are moremature and better able to concentrate urine. With all of these changes, the child isready to begin a new approach to eating.

New foods are added one at a time to monitor for food allergiesThe most commonly recommended food to be fed first to a child is iron-fortified in-fant rice cereal mixed with formula or breast milk. Rice cereal is the recommendedfirst food because it is easily digested and rarely causes allergic reactions. After rice hasbeen successfully included in the diet, other grains can be introduced, with wheat ce-real given last because it is most likely to cause an allergic reaction. After cereals are in-troduced, puréed vegetables or fruits can be tried; some suggest that vegetables beoffered before fruits so that the child will learn to enjoy food that is not sweet beforebeing introduced to sweet foods. Once teeth have erupted, foods with more texture

You may have heard that addinginfant cereal to a baby’s bottleduring the first few months will helpthe child sleep through the night, butstudies have shown that this practicedoes not alter sleep patterns.

can be added. For the 6- to 12-month-old child, small pieces of soft or ground fruits,vegetables, and meats are appropriate (Table 12.3).

Each new food should be offered for a few days without the addition of any othernew foods. If an allergic reaction occurs, it is most likely due to the newly introducedfood. Foods that cause symptoms such as rashes, digestive upsets, or respiratory prob-lems should be discontinued and the symptoms resolved before any other new foodsare added.

Food allergies occur when the immune system reacts toa food Food allergies are common in infants because their digestive tracts are notfully mature, therefore allowing the absorption of incompletely digested proteins,which trigger a response from the immune system (see Chapter 3, Your Choice :When Food is the Foe). Exposure to an allergen for the first time causes the immunesystem to produce antibodies to that allergen. When the allergen is encountered againby eating the same food, allergy symptoms such as vomiting, diarrhea, asthma, hives,eczema, runny nose, hay fever, and general cramps and aches may result as the im-mune system battles the allergen. The symptoms may occur almost immediately ortake up to 24 hours to appear, and can vary from mild to severe and life-threatening.Foods that commonly cause allergies in children include eggs, milk, peanuts, soy, andwheat.

After about 3 months of age, the risk of developing food allergies is reduced be-cause incompletely digested proteins are less likely to be absorbed. Many children whodevelop food allergies before the age of 3 will outgrow them. For example, most chil-dren allergic to eggs at 1 year of age, will no longer be allergic at age 5. Allergies thatappear after 3 years are more likely to be a problem for life.

True food allergies are relatively rare, occurring in about 6% of children under 3 and1.5% of adults.38 In contrast to food allergies, food intolerances do not involve anti-body production by the immune system. Rather, they are caused by foods that createproblems during digestion. Food intolerances can be the result of chemical compo-nents in foods, toxins that occur naturally in foods, substances added to foods duringprocessing or preparation, or simply large amounts of foods, such as onions or prunes,that cause local GI irritation. Lactose intolerance is an example of a food intolerancecaused by a reduced ability to digest milk sugar. It is not an allergy to milk proteins.

Solid Food Can Be Introduced between 4 and 6 Months of Age 435

Unmodified cow’s milk should neverbe fed to infants; its higher proteinand mineral content taxes thekidneys and predisposes the infantto dehydration. Young infants mayalso become anemic if fed cow’smilk because it contains littleabsorbable iron and can lead toiron loss by causing small amountsof gastrointestinal bleeding.

T A B L E 1 2 . 3Infants Need to Eat Frequently to Meet Their Needs

A Typical Day Should Include the Following Servings

Food Serving Size 4–6 Months 6–8 Months 9–12 Months

Tongue does not Can easily move Can use a cup and easily push food out hand to mouth consume finger foods

Formula or breast milk* 8 oz 4 4 4

Dry infant cereal 2 Tbsp 2 4 4

Vegetables 2–3 Tbsp — 2 3

Fruits 2 Tbsp — 2 4

Fruit juice 4 oz — — 1

Meats (or egg yolks) 1 Tbsp — 2–4 (strained) 4–6 (chopped)

Finger foods Varies — 1† 4‡

*Includes that added to cereal.†Dry toast, teething biscuits.‡Table foods except “choking” foods (foods in shapes and sizes that are likely to cause choking, such as large pieces of meat,whole grapes, or hot dogs or carrots cut in circular slices).

Allergen A substance that triggers anallergic reaction.�*

Food intolerance An adverse reactionto a food that does not involve a specificresponse from the immune system.

�*


A food challenge can confirm the presence of a food al-lergy If you suspect a food allergy there are several laboratory methods that canidentify foods that are likely to be the cause of an individual’s allergic reaction, butthey cannot determine the source of the problem with 100% reliability. The cause of afood allergy can be confirmed by using an elimination diet and food challenge. Thisinvolves removing all foods suspected of causing an allergic reaction from the diet.When a diet that causes no symptoms has been established, it is followed for 2 to 4weeks. Then, in the food challenge, small amounts of a food suspected of causing a re-action are reintroduced under a doctor’s supervision. If no reaction to the food occurs,then increasing amounts are introduced until a normal portion is offered. If there isstill no reaction, then the food can be ruled out as an allergen.

Allergies can’t always be prevented but can be man-aged Breast-feeding can reduce the risk of food allergies and is recommended forinfants from families with a history of allergies. Infants who are breast-fed are lesslikely to be exposed to foreign proteins that cause food allergies. In addition, their gutmatures earlier and they are protected by antibodies and other components of humanmilk.39 The benefits of breast-feeding are increased if the mother avoids eating com-mon allergy-causing foods such as peanuts, eggs, fish, and dairy products during lacta-tion. To decrease the chances of developing allergies when solid foods are introduced,wheat, eggs, and fish should not be introduced until the child is 12 months of age,and peanuts should not be given until 36 months. Even with these precautions it isnot always possible to prevent the development of a food allergy.

The best way to manage a food allergy is to avoid consuming the offending food.The information on food labels can be helpful in identifying foods that containallergy-causing ingredients (see Chapter 6, Off the Label: Is it Safe for You?).

As the baby develops appropriate foods can be offeredAs the child becomes familiar with more variety, food choices should be made fromeach of the food groups in the Food Guide Pyramid. At 1 year of age, whole cow’smilk can be offered and continued until 2 years of age, after which reduced fat milks

Elimination diet and food challengeA program that eliminates potential allergy-causing foods from an individual’s diet andthen systematically adds them back toidentify any foods that cause an allergicreaction.

�*

F I G U R E 1 2 . 2 3

Self-feeding is an important part of normal infantdevelopment. (Geoff Manasse/Aurora Photos)

An allergy to peanuts is particularlydangerous because reactions tendto be severe and occur when anallergic person is exposed toamounts of peanut protein as lowas 100 �g. For other food allergies,up to 1,000-fold more—50–100 mgof an allergen—must be ingestedbefore a reaction occurs.

can be used. To avoid choking, foods that can easily lodge in the throat, such as car-rots, grapes, and hot dogs, should not be offered to infants or toddlers.

As children become more independent, they will want to feed themselves. Al-though this is not always a neat and clean process, it is important for development. Bythe age of 8 or 9 months, infants can hold a bottle and self-feed finger food such ascrackers (Figure 12.23). By 10 months, most infants can drink from a cup, so waterand fruit juices can be offered. Juice should not be served in a bottle because it maycontribute to nursing bottle syndrome. Excess quantities of apple and pear juiceshould be avoided; they contain sorbitol, a poorly absorbed sugar alcohol, that cancause diarrhea. Added sugars should be offered in moderation to ensure a nutrient-dense diet. Honey and corn syrup should not be fed to children less than a year oldbecause these foods may contain spores of Clostridium botulinum, the bacterium thatcauses botulism poisoning (see Chapter 14). Older children and adults are not at riskfrom botulism spores because the environment in a mature gastrointestinal tract pre-vents the bacteria from growing.

Summary 437

T H I N K I N G F O R Y O U R S E L F

1. If you were a 25-year-old pregnant woman, would yourdiet meet your needs?a. Pick one day of the food record you kept in Chapter

2. Does this diet meet the calorie and protein needs ofa 25-year-old pregnant woman? If not, what foodswould you add to the diet to meet the needs ofpregnancy?

b. Does this diet meet the iron and calcium needs of a25-year-old pregnant woman? List three foods that are good sources of each.

c. Does this diet meet the folate needs of a 25-year-oldpregnant woman? What foods could you add to a diet that is low in folate to meet needs withoutsupplements? What foods in this diet are fortified with folic acid?

2. How do the nutrient needs of a nonpregnant, pregnant,and lactating woman of the same age and size differ?

a. For each of the following nutrients, describe anydifferences between the needs of nonpregnant,pregnant, and lactating women:• Energy• Protein• Calcium• Iron• Folate

b. For each of the above nutrients explain why therequirements for pregnancy and lactation do or do not differ from those for the nonpregnant state.

3. Is there a WIC program in your area?a. Use the Internet to find the nearest WIC program.b. Would it be easy for you to use this program if you

were a pregnant or lactating woman or had a youngchild?

c. What income levels does it serve?

S U M M A R Y

1. Babies all begin as a fertilized egg. During the first 8weeks of development, all of the organ systemsnecessary for life are formed in the embryo. Over theremaining weeks of pregnancy, the fetus grows and theorgans continue to develop and mature. The placentatransfers nutrients from the mother’s blood to nourishthe developing child. At birth, a healthy baby weighs5.5 to 8.8 pounds. Infants smaller or larger than this areat increased risk.

2. During pregnancy, the mother’s body undergoes manychanges to support the pregnancy and prepare forlactation. The placenta develops; the maternal bloodvolume increases; the uterus and supporting muscles

expand; the heart, lungs, and kidneys work harder; thebreasts enlarge; body fat is deposited and total bodyweight increases.

3. Recommended weight gain during pregnancy is 25 to35 pounds for normal-weight women. If too littleweight is gained, the infant may be small at birth and atincreased risk for illness and death. Too much weightgain can place both mother and baby at risk, but weightloss should never be attempted during pregnancy.Normal-weight, underweight, and overweight mothersshould gain weight at a steady rate during pregnancy.

4. During healthy pregnancies, a carefully planned programof moderate-intensity exercise can be beneficial and safe.


5. The hormones that direct changes in maternalphysiology and the growth and development of thefetus sometimes cause unwanted side effects. Changesin fluid volume may cause edema. Digestive systemdiscomforts that are common in pregnancy includemorning sickness, heartburn, constipation, andhemorrhoids.

6. During pregnancy the requirements for energy, protein,water, vitamins, and minerals increase. The B vitaminsare needed to support increased energy and proteinmetabolism; calcium, vitamin D, and vitamin C areneeded for bone and connective tissue growth; protein,folate, vitamin B12, and zinc are needed for cellreplication; and iron is needed for red blood cellsynthesis. Supplements containing iron and folic acidare recommended.

7. Because the embryo and fetus are rapidly developingand growing, they are susceptible to damage from poornutrition and physical, chemical, or otherenvironmental teratogens. Severe defects indevelopment often result in miscarriage. Foodsconsumed due to food cravings are generally safe unlessnonfood items are craved. Environmental toxins such asmercury in fish cause birth defects. Exposure tocigarette smoke causes low birth weight. Alcoholconsumption during pregnancy is a leading cause ofmental retardation and other birth defects. The use of illegal drugs such as cocaine also increases the risk of low birth weight and birth defects.

8. Complications during pregnancy increase risk formother and child. Gestational diabetes involves a highblood sugar in the mother that provides extra calories tothe growing baby. Pregnancy-induced hypertension mayinvolve high blood pressure (gestational hypertension),edema, weight gain, and protein in the urine(preeclampsia), and in severe cases can be life-threatening (eclampsia).

9. Nutritional status, income, and age affect pregnancyoutcome. Risks of pregnancy are increased by poornutritional status before pregnancy; poverty, whichlimits access to food and health care; age that is under20 years because the mother is still growing, or over 35years because the mother is more likely to havepreexisting health conditions.

10. During lactation the need for protein, fluid, and manyvitamins and minerals is even greater than duringpregnancy.

11. Newborns grow more rapidly and require more energyand protein per kilogram of body weight than at anyother time in life. Fat and fluid needs are alsoproportionately higher than in adults. A diet that meetsenergy, protein, and fat needs may not necessarily meetthe need for iron, fluoride, and vitamins D and K.Growth is the best indicator of adequate nutrition inthe infant.

12. Breast milk is the ideal food for new babies. It is designedspecifically for the human newborn; it is always available;it requires no special equipment, mixing, or sterilization;and it provides immune protection. If breast-feeding isnot chosen, there are many infant formulas on the marketthat are patterned after human milk and provide adequatenutrition to the baby. Formula is the best option when themother is ill or is taking prescription or illicit drugs, orwhen the infant has special nutritional needs.

13. Introducing solid foods between 4 and 6 months of ageadds iron and other nutrients to the diet and aids inmuscle development. Newly introduced foods should beappropriate to the child’s stage of development andoffered one at a time to monitor for food allergies. Foodallergies occur when the immune system reacts to afood. They can be confirmed by an elimination diet anda food challenge. Food intolerances cause GI symptomsbut are not caused by antibody production by theimmune system.

R E V I E W Q U E S T I O N S

1. Why is the adequacy of the mother’s diet so importantearly in pregnancy?

2. List three physiological changes that occur in themother’s body during pregnancy.

3. How much weight should a woman gain duringpregnancy?

4. How do the recommendations for weight gain differ foroverweight and underweight women?

5. What kind of exercise is safe during pregnancy?6. How do the requirements for energy and protein

change during pregnancy?7. Why does the mother’s recommended intake for iron

increase during pregnancy?8. How do a woman’s energy and protein requirements

change during lactation?

9. How does alcohol consumed by a woman duringpregnancy affect the child?

10. Why does gestational diabetes cause babies to be borntoo big?

11. How does maternal age affect nutrient requirementsduring pregnancy?

12. Why do babies need a higher fat diet than adults?13. What are the advantages of breast-feeding?14. When is bottle-feeding a better choice?15. When should solid and semisolid foods be introduced

into an infant’s diet?16. Why is it important to introduce new foods one at a

time?17. What steps can caregivers take to reduce the risk of a

child developing food allergies?

R E F E R E N C E S

1. Committee on Nutritional Status during Pregnancy andLactation, National Academy of Sciences. Nutrition DuringPregnancy. Washington, DC: National Academy Press, 1990.

2. Bryson, S. R., Theriot, L., Ryan, N. J., et al. Primary follow-upcare in a multidisciplinary setting enhances catch-up growth ofvery-low-birth-weight infants. J. Am. Diet. Assoc. 97:386–390,1997.

3. American College of Sports Medicine. ACSM’s Guidelines forExercise Testing and Prescription, 6th ed. Baltimore: LippincottWilliams & Wilkins, 2000.

4. Food and Nutrition Board, Institute of Medicine. DietaryReference Intakes for Energy, Carbohydrates, Fiber, Fat, Protein andAmino Acids. Washington, DC: National Academy Press, 2002.

5. Food and Nutrition Board, Institute of Medicine. DietaryReference Intakes for Water, Potassium, Sodium, Chloride, andSulfate. Washington, DC: National Academy Press, 2004.

6. Food and Nutrition Board, Institute of Medicine. DietaryReference Intakes for Calcium, Phosphorus, Magnesium, Vitamin D,and Fluoride. Washington, DC: National Academy Press, 1997.

7. Food and Nutrition Board, Institute of Medicine. DietaryReference Intakes for Vitamin C, Vitamin E, Selenium, andCarotenoids. Washington, DC: National Academy Press, 2000.

8. Scholl, T. O., and Johnson, W. G. Folic acid: Influence on theoutcome of pregnancy. Am. J. Clin. Nutr. 71(Suppl.):1295S–1303S,2000.

9. Food and Nutrition Board, Institute of Medicine. DietaryReference Intakes for Thiamin, Riboflavin, Niacin, Vitamin B-6,Folate, Vitamin B-12, Pantothenic Acid, Biotin, and Choline.Washington, DC: National Academy Press, 1998.

10. King, J. C. Determinants of maternal zinc status duringpregnancy. Am. J. Clin. Nutr. 71(Suppl.):1334S–1343S, 2000.

11. Food and Nutrition Board, Institute of Medicine. DietaryReference Intakes for Vitamin A, Vitamin K, Arsenic, Boron,Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel,Silicon, Vanadium, and Zinc. Washington, DC: National AcademyPress, 2001.

12. Allen, L. H. Anemia and iron deficiency: Effects on pregnancyoutcome. Am. J. Clin. Nutr. 71(Suppl.):1280S–1284S, 2000.

13. Mitchell, M. K. Nutrition Across the Life Span. Philadelphia: W. B.Saunders, 1997.

14. Rose, E. A., Porcerelli, J. H., and Neale, A. V. Pica: Common butcommonly missed. J. Am. Board Fam. Pract. 13:353–358, 2000.

15. U.S. DHHS and U.S. EPA. FDA and EPA announce the revisedconsumer advisory on methylmercury in fish. Available online atwww.fda.gov/bbs/topics/news/2004/NEW01038.html/AccessedAugust 25, 2004.

16. Magee, B. D., Hattis, D., and Kivel, N. M. Role of smoking inlow birth weight. J. Reprod. Med. 49:23–27, 2004.

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18. National Center for Chronic Disease Prevention and HealthPromotion. Women and Smoking: A Report from the SurgeonGeneral 2001. Available online at www.cdc.gov/tobacco/sgv/index.htm/Accessed August 25, 2004.

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24. Fajemirokun-Odudeyi, O., and Lindow, S. W. Obstetricimplications of cocaine use in pregnancy: A literature review.Eur. J. Obst. Gyncol. Reprod. Biol. 112:2–8, 2004.

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26. Centers for Disease Control and Prevention. National Agenda for Public Health Action: A National Public HealthInitiative on Diabetes and Women’s Health. Available online at www.cdc.gov/diabetes/pubs/action/facts.htm/Accessed August 25, 2004.

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