Exercise in pregnancy

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Table of contents Physiologic changes in pregnancy Type, intensity, and frequency of exercise Benefit of exercise in pregnancy Contraindications of exercise in pregnancy Warning signs to terminate exercise while

pregnant Maternal advice after exercise recommenda-

tion Exercise in postpartum

Physiologic changes in pregnancy

Nutritional requirement Cardiovascular changes Respiratory changes Mechanical changes Thermoregulatory changes Metabolic changes

Nutritional requirement After the 13th weeks of pregnancy, about 300kcal per

day are required to meet the metabolic needs of pregnancy

This energy requirement is increased through exer-cise.

In weight bearing exercise, such as walking, the en-ergy requirement progressively increases with the increase in weight during the course of the preg-nancy.

A related consideration to nutrition and exercise dur-ing pregnancy is adequate carbohydrate intake.

Artal et al, 2003

Cardiovascular changes

Pregnancy induces – increase in maternal blood volume, cardiac output, and

resting pulse – decrease in maternal systemic vascular resistance.

– Hemodynamics depends on position– Cardiac output in third-trimester pregnancy is maximal

– in the left or right lateral recumbent position.

– Decreased cardiac output– Supine position– Motionless standing Clark et al, 1991

Jovanovic-Peterson et al, 1989

Respiratory changes During pregnancy minute ventilation increases by almost

50%, largely as a result of increased tidal volume.

– increase in arterial oxygen tension to 106-108 mmHg in the first trimester, decreas-ing to a mean of 101-106 mmHg by the third trimester.

– increase in oxygen uptake, and a 10-20% increase in baseline O2 consumption.

– Because of the increased resting oxygen requirements and the increased work of breathing brought about by physical effects of the enlarged uterus on the di-aphragm, there is decreased oxygen available for the performance of aerobic exer-cise during pregnancy.

– in some fit women, there do not appear to be associated changes in maximum aer-obic power or acid-base balance during exercise in pregnancy when compared with the nonpregnant state

Artal et al. 1986, Prowse et al.1965

Templeton et al,1976

Mechanical changes The enlargement of uterus and breasts that

occurs during normal pregnancy results in a shift in the physical center of gravity in the pregnant woman. – loss of balance may prove dangerous

Hormonal influences may result in general-ized increases in joint laxity, predisposing the pregnant woman to mechanical trauma or sprains.

Calguneri et al. 1982, Artal etal.1991

Thermoregulatory changes Both basal metabolic rate and heat production increase

during pregnancy

Teratogenecity – 39.2°C, with hot tub use in early pregnancy– an increase in maternal core body temperature during embryo-

genesis exceeding 1.5°C has been observed to cause cessation of neuronal mitotic cell growth in the ependymal layer of the de-veloping brain.

– Nonpregnant women exercising at 70% of maximal effort on a treadmill for 20 minutes, the core body temperature rose by an average of 1.5°C.

– Fit individuals are known to thermoregulate their core tempera-ture more efficiently.

Hytten et al.1980, Artal et al.1991, Edwards et al.1986, Milunsky et al.1992

2002 ACOG recommendationExercise in pregnancy

In the absence of either medical or obstetric com-plications during pregnancy

women should perform 30 minutes or more of moderate-intensity exercise on most, if not all, days of the weeks.

Moderate exercise – Defined as activity for 30 or more minutes a day, 5 or more

days a week– ex. : Brisk walking, bicycling, vacuuming, gardening, or any activity

that causes small increases in breathing or heart rate

ACOG, 2002

Centers for Disease Control, US physical activity statistics: definitions. 2006

Type of exerciseSafe Avoid

Aerobic exercise Progressive resistive strengthen-ingStretching exercisesYogaStationary bicyclingJoggingWalkingStair climbingTreadmill useWater exerciseSwimming

Supine position after the first trimesterMotionless standing

Recreational sports with a high potential for contact, such as ice hockey and baseball

Increased risk of falling, such as horseback riding and gymnas-tics

Advised not to scuba dive be-cause the fetus is at risk of de-compression sickness

Artal et al. 1991, Clark et al.1991, Camporesi et al. 1996 , ACOG 2002

Intensity of exercise ACSM(American college of sports medicine) recommend

that intensity should be 60-90% of maximal heart rate or 50-85% of either maximal oxygen uptake or heart rate re-serve.

60 % of maximal heart rate or 50% of maximal oxygen uptake– for most pregnant women who did not engage in regular exer-

cise before pregnancy

70% of maximal heart rate or 60% of maximal oxygen up-take– for those who wish to continue to maintain fitness during preg-

nancy.Artal et al, 2003

Intensity of exercise

Daries et al, 2003

Frequency of exercise and rate of progres-sion

Previously sedentary women– Start with 15 min of exercise three times a week– Gradually increase to 30 min four times a weeks at low

to moderate intensity

Active women– Keep their routine exercise or perform at least moderate-

to-vigorous exercise – Four times a week in sessions of 30min or more

Atheletes or women who have higher fitness sta-tus– Evaluated individually– The intensity of exercise like running should be reduced

Davies et al, 2003

Benefits of exercise and activity during preg-nancy

Decreased chance of preeclampsia, second lead-ing cause of maternal death

Decreased chance of operative delivery Decreased chance of developing gestational dia-

betes Improved mood Reduction of pregnancy discomforts- backache

and lower extremity edema Possible prevention of type II diabetes Possible prevention of chronic hypertension

ACOG, 2002

Pre-eclamapsia

Tanya et al., 2003

Pre-eclamapsia

Kasawara et al., 2012

Tinoloy et al., 2014

Deomendoz et al., 20140

Exercise intervention (cesarean deliv-ery)

Deomendoz et al., 2014

Birthweight

Juhl, et al, 2010

Gestational diabetes mellitus Epidemiologic data suggest that exercise may be ben-

eficial in the primary prevention of gestational dia-betes, particularly in morbidly obese women (BMI >33)

The American Diabetes Association has endorsed exer-cise as “a helpful adjunctive therapy” for gestational diabetes mellitus when euglycemia is not achieved by diet alone

Vigorous activity : RR, 0.77 (95% CI, 0.69-0.94). Brisk walking pace : RR, 0.66 (95% CI, 0.46-0.95) com-

pared with an easy pace.

Dye et al, 1997

Jovanovic-Peterson et al 1996, Bung et al.,1996

Zhang et al, 2006

ACOG contraindications to exercise in pregnancy

Hemodynamically significant heart disease Restrictive lung disease Incomplete cervix/cerclarge Multiple gestation at risk for premature labor Persistent second- or third trimester bleeding Placenta previa after 26weeks of gestation Premature labor during current pregnancy Ruptured membranes Preeclampsia

ACOG,2002

ACOG relative contraindications to aerobic exercise during pregnancy

Severe anemia Unevaluated maternal cardiac arrhythmia Chronic bronchitis Poorly controlled type 1 diabetes Extreme morbid obesity Extreme underweight (BMI < 12) History of extremely sedentary lifestyle IUGR in current pregnancy Poorly controlled hypertension Orthopedic limitations Poorly controlled seizure disorder Poorly controlled hyperthyroidism Heavy smoker

ACOG,2002

Warning signs to terminate exercise while pregnancy

Vaginal bleeding Dyspnea prior to exertion Dizziness Headache Chest pain Muscle weakness Calf pain or swelling (need to rule out throm-

bophlebitis) Preterm labor Decreasing fetal movement Amniotic fluid leakage

ACOG,2002

Maternal advice after exercise recom-mendation

Should aware of uterine contractions Less than the fetal movements in 12 hours

is an indication that further investigation at a hospital is warranted

No longer suggest the routine counting of fetal movements in the second half of a woman’s pregnancy

NICE Guideline, 2004

Exercise in postpartum Many of the physiologic and morphologic changes

of pregnancy persist 4-6 weeks postpartum. Thus, prepregnancy exercise routines should be

resumed gradually based on a woman’s physical capability.

No known maternal complications are associated with resumption

Decreased incidence of postpartum depression and stress relieving

Hale et al, 1996

Koltyn et al, 1997

ACOG, 1994; ACOG 2002

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