Current medical practice recommends that pregnant women should most assuredly engage in some sort of exercise regimen while pregnant. Yet what is the effect of exercise on pregnancy? Exercising during pregnancy is good for the mother; there is no doubt about it. Pregnant women who exercise tend to have reduced risk of obesity, gestational diabetes, hypertension, and preeclampsia. However, the effects on the fetus are unclear. (1,2)
One very large Danish study consisting of 87,232 pregnant women studied the effects of exercise during pregnancy on preterm births. This study concludes that any sort of exercise during pregnancy leads to a reduced risk of preterm birth, which is good news. Interestingly, it seems any kind of exercise no matter how light is better than no exercise at all in terms of preventing preterm birth. There was no indication that exercising harder was any better than exercising just a little bit. They did find that exercising late in pregnancy leads to a reduced risk of preterm birth, while early exercise showed no differences. While it is uncertain if exercise provides an actual protective effect against preterm birth, this study hints at an association and no negative effects were reported. Some adverse effects from rigorous exercise have been reported, so it is better to exercise lightly or moderately. (3)
Another interesting study, this one randomized and controlled, on water aerobics and pregnancy concluded similar findings: there were no adverse outcomes to the mother or fetus from physical activity. The results of this study found further benefits in that the group that participated in water aerobics had much less need for analgesics during labor, a 58% reduction. (4)
Several other studies have concluded that exercise in pregnancy leads to a slight reduced birth-weight and BMI of the infant. This is actually good news since higher birth-weight is correlated with increased risk of obesity later on. Thus, exercise in pregnancy may have long-term health benefits for one’s children. Benefits again were seen when pregnant women engaged in exercise during the second-half of pregnancy. (5)
Thus, there seem to be benefits for the child as well as the mother. The ACOG guidelines for exercise during pregnancy are helpful for any pregnant women interested in starting up an exercise regimen. Please check out their guidelines for more information.
References:
1. Dye TD, Knox KL, Artal R, et al. Physical activity, obesity, and diabetes in pregnancy. Am J Epidemiol (1997) 146:961–5.
2. Sorensen TK, Williams MA, Lee IM, et al. Recreational physical activity during pregnancy and risk of preeclampsia. Hypertension (2003) 41:1273–80.
3. Juhl, M., P. K. Andersen, et al. (2008). "Physical exercise during pregnancy and the risk of preterm birth: a study within the Danish National Birth Cohort." Am J Epidemiol 167(7): 859-866.
4. Baciuk, E. P., R. I. Pereira, et al. (2008). "Water aerobics in pregnancy: Cardiovascular response, labor and neonatal outcomes." Reprod Health 5: 10.
5. Hopkins, S. A., J. C. Baldi, et al. (2010). "Exercise training in pregnancy reduces offspring size without changes in maternal insulin sensitivity." J Clin Endocrinol Metab 95(5): 2080-2088.
