Exercise During Pregnancy
Moderate Activity Poses No Risk to Pregnant Women or Their Babies
Jul 30, 2009
In January 2002, the American College of Obstetricians and Gynecologists (ACOG) disseminated an opinion statement regarding exercise during pregnancy: “In the absence of either medical or obstetric complications, 30 minutes or more of moderate exercise a day on most, if not all, days of the week is recommended for most pregnant women.” (ACOG Committee Obstetric Practice. ACOG Committee Opinion, No. 267, January 2002: exercise during pregnancy and the postpartum period. Obstet Gynecol 2002;99:171-3)
Strangely, a Cochrane review published in the same month indicated that the available data defining benefit or risk to a mother or fetus was insufficient to make a recommendation regarding aerobic exercise during pregnancy. (Kramer M. Aerobic exercise for women during pregnancy. Cochrane Database Syst Rev 2004;(1): CD000180)
Although these two philosophies may seem to be at odds, it helps to examine the reasoning behind their conclusions.
ACOG based its recommendation on a number of small, observational studies and a few well-controlled trials.
Cochrane reviews are based not only upon the outcomes of the studies included in the review; they heavily weigh the statistical designs of those studies. Any weakness in design (e.g., small study groups, retrospective analyses, inconsistencies in methodology, etc.) also weakens the review.
Thus, Cochrane reviews often seem waffling in their conclusions and—because they analyze completed trials—may lag slightly behind the knowledge curve.
More recent information reinforces the idea that exercise during pregnancy is not only beneficial to a mother’s emotional wellbeing; regular moderate activity (barring contraindications) confers significant health benefits to both mother and fetus.
Exercise During Pregnancy Reduces Obesity for Mothers and Their Children
- Women who exercise during pregnancy are less likely to gain excessive weight; this, in turn, significantly reduces their chances of being obese eight to ten years later. (Rooney B, Schauberger C. Excess pregnancy weight gain and long term obesity: one decade later. Obstet Gynecol 2002;100:245-52)
- Women who exercise vigorously during pregnancy deliver leaner infants as a result of restricted fetal fat accumulation; it has been suggested that these infants are less likely to become obese later in life. (Magann E, et al. Antepartum, intrapartum, and neonatal significance of exercise on healthy low-risk pregnant working women. Obstet Gynecol 2002;99:466-72)
Exercise Reduces the Risk for Complications During Pregnancy and Delivery
- Gestational diabetes: Moderate aerobic exercise, in addition to controlling weight gain (an independent risk factor for maternal diabetes), also improves the metabolism of glucose, even in women who already have gestational diabetes. (Avery M, Walker A. Acute effect of exercise on blood glucose and insulin levels in women with gestational diabetes. J Matern Fetal Med 2001 10(1):52-8)
- Pregnancy-induced hypertension (pre-eclampsia): Regular maternal exercise reduces the risk for developing pre-eclampsia, possibly by decreasing oxidative stress. (Dempsey J, et al. No need for a pregnant pause: physical activity may reduce the occurrence of gestational diabetes mellitus and preeclampsia. Exerc Sport Sci Rev 2005. 33(3):141-9)
- Premature delivery (preterm birth): Consistent exercise during pregnancy appears to reduce the risk for preterm birth. (Juhl M, et al. Physical exercise during pregnancy and the risk of preterm birth: a study within the Danish National Birth Cohort. Clin J Sport Med 2009;19(3):241-3)
Accumulating evidence confirms that exercise during pregnancy is not only safe; it appears to improve pregnancy outcomes. Potential risks for harm from exercise are rare in properly screened women—adequate prenatal care, then, is part of the prescription for a healthy, uneventful pregnancy.
Avoidance of extreme environmental conditions (e.g., excessive heat or cold) and situations that can lead to abdominal trauma are important considerations in the development of an exercise program.
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