chapter 15 pregnancy & lactation prior to pregnancy goals-essential to conception & healthy...

Chapter 15

Pregnancy & Lactation

Prior To Pregnancy

• Goals-essential to conception & healthy infant development– Achieve and maintain a healthy

body weight– Choose an adequate and balanced

diet– Be physically active– Avoid harmful influences

Copyright 2005 Wadsworth Group, a division of Thomson LearningCopyright 2005 Wadsworth Group, a division of Thomson Learning

Fetal Growth & Development• Ovum + sperm zygote

• Zygote – the first 2weeks after fertilization– Implantation

• Embryo – 2 to 8 weeks after conception

• Fetus – from 8 weeks after conception to full-term


Critical Periods-if cell division and number are limited during a critical period full recovery is not possible


Critical Periods• Neural tube defects

– Anencephaly-the neural tube fails to close so the brain is either missing or fails to develop

– Spina bifida-incomplete closure of the spinal cord and its bony encasement

• Folate supplementation reduces the risk


Weight Prior To Conception• Increased medical risks if a woman is

under- or overweight prior to pregnancy• Prepregnancy weight affects development

of healthy support tissues – placenta, amniotic sac, etc.

• Prepregnancy weight affects infant birthweight – Infant birthweight is the most potent

predictor of infant’s future health & survival


Weight Prior To Conception

• Underweight– Preterm

• Overweight and obesity– Post term– Cesarean section– Dieting is dangerous because ketosis

from fasting/low-CHO diets impairs fetal brain development


Weight Gain


Nutrient NeedsEnergy – Extra food energy needed

1. No additional allowance is provided during the 1st trimester 2. During the 2nd & 3rd trimesters RDA + 350-450 kcals/day 3. More if teenager, underweight, very active, or multiple gestationProtein – RDA +25 grams/day (~70 gms); usually not a problem since most diets already exceed recommendation

Nutrient NeedsVitamins – Folate & Vitamin B12 needed in

large amounts for rapid cell proliferationFolate needed for increased red blood cells and to help prevent neural tube defects

1. Recommendation increases from 400 micrograms/day during childbearing years to 600 micrograms/day during pregnancy usually from supplementsVitamin B-12 – RDA during pregnancy is 2.6 mcg/day; supplements recommended for vegans

Nutrient Needs• Minerals needed for:

1. Bones & teeth – calcium, phosphorous, magnesium & fluoridefluoride involved in involved in

building the skeletonbuilding the skeleton2. Blood – iron necessary for 50%

increase in maternal blood volume and accumulation of fetal iron stores during the 3rd trimester

3. Protein synthesis- zinc vital for DNA & RNA synthesis

Nutrient Needs

Calcium – 1200 mg/day recommended to conserve maternal bone mass while

supplying fetal needsFlouride – supplements not recommended

if water flouridatedIron – increased need cannot be met by diet

or existing stores so supplements (30 mg/day) recommended during 2nd & 3rd trimesters

High-Risk Pregnancies


Food Assistance Programs

WIC Program – helps low income pregnant women & their children (<5 years) obtain needed food and nutrition education for growth & development and to reduce the risks of preterm or low-birth weight infants

Maternal HealthPreexisting Diabetes or Gestational Diabetes –

high blood glucose can lead to fetal (macrosomia) & delivery complications

1. Usually dx’d in 2nd or 3rd trimester by glucose tolerance test; screening at 24-28 weeks gestation 2. Dietary control involves avoiding simple sugars, eating small, frequent meals/snacks, and preventing excessive weight gain 3. 1/3 of women will go on to develop diabetes in future

Maternal Health

Preexisting Hypertension or Preeclampsia– high blood pressure may be preexisting condition or may be pregnancy-induced signaling onset of preeclampsia (condition

characterized by high blood pressure, generalized edema, & proteinuria) 1. Control involves good nutrition (esp. calcium) & bedrest

Nutrition-Related Concerns• Nausea• Constipation and hemorrhoids• Heartburn• Food cravings and aversions- due to

hormone-induced changes in sensitivity to taste and smell instead of reflecting true physiological needs

• Nonfood cravings – laundry starch, clay, soil, ice– Pica is associated with iron deficiency

anemia


Maternal DiscomfortsNausea/Morning Sickness – caused by

hormonal changes early in pregnancy (increased levels of hCG)

• Ways to Alleviate1. On waking, rise slowly2. Eat dry toast or crackers in morning3. Eat small, frequent low-fat meals 4. Avoid strong or offensive food odors

• Severe cases – hyperemsis gravidarum; usually require rehydration & hospitalization

Maternal DiscomfortsHeartburn – as baby grows, pressure on

mother’s stomach increases causing reflux• Ways to Alleviate

1. Eat small, frequent meals slowly2. Drink liquids between meals3. Avoid spicy or greasy foods 4. Avoid lying down for right after eating

and elevate the head while sleeping

Maternal DiscomfortsConstipation – slower GI motility• Ways to Alleviate

1. Increase fluid intake to8 glasses a day2. Eat foods high in fiber (fruits,

vegetables, whole-grain cereals) 3. Exercise regularly

4 Use laxatives only as prescribed by a physician; do not use mineral oil because it interferes with the absorption of fat-soluble vitamins

Practices Incompatible with Pregnancy

1. Cigarette smoking – restricts blood supply to fetus, impairing fetal nutrition & increases risk of low birth weight and SIDS infants

2. Caffeine – limit to 1 cup “coffee”/day or may lower infant birthweight

3. Medicinal Drugs – prescription meds only with M.D. approval due to risk of birth defects

Practices Incompatible with Pregnancy

4. Illicit drugs, such as cocaine or marijuana, also pass through placenta

causing toxicity & central nervous system damage

5. Herbal supplements6. Vitamin/mineral megadoses are toxic7. Sugar substitutes in moderation8. Alcohol may cause fetal alcohol

syndrome (severe mental & physical retardation) & interferes with transport of nutrients across placenta

Fetal Alcohol Syndrome


Lactation• Mammary glands- secrete milk• Prolactin – hormone responsible for milk production• Oxytocin-hormone that causes milk to eject• Let-down reflex


Mother’s Nutrient Needs During Lactation

• Energy Needs – additional 500 kcals/day needed to produce

~25 oz. milk/day provided by food & fat reserves (stored energy)

1. Breastfeeding can facilitate maternal weight loss

2. Avoid diets - <1200 kcals/day compromises milk production


• Fluids - >2 qts./day to prevent dehydration

• Prenatal vitamin supplements routinely prescribed

- RDAs same or slightly higher for most nutrients except iron until menstruation resumes


• Recommendation for protein the same as during pregnancy

• Vitamins & Minerals – supplements generally recommended to replete maternal stores; prolonged inadequate intakes reduce the quality of the milk

• Water – 3 L/day to prevent dehydration

Lactation• Certain foods, esp. with strong or spicy

flavors, are avoided only if baby seems sensitive

• Caffeine may cause irritability & difficulty sleeping• Alcohol easily enters breast milk• Smoking decreases milk production• Medicinal Drugs – most are compatible but

need to check with physician for those contraindicated

• Illicit Drugs – high doses delivered in breast milk

Lactation

• Breastfeeding considered the “gold standard” for infant feeding due to immunologic, health & social benefits

• Contraindications – Communicable diseases (TB, hepatitis, HIV, etc.) and certain meds/drugs that

adversely affect infant

Energy & Nutrient Needs



Nutrient Needs

chapter 15 pregnancy & lactation prior to pregnancy goals-essential to conception & healthy...

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