Study: How Exercise Might Improve Pregnancy

A new study re-examining previous clinical trial data associating exercise during pregnancy and preterm birth revealed that exercise during pregnancy is safe and does not increase the risk of preterm birth.

The study, published in the American Journal of Obstetrics and Gynecology, also suggests that women who exercise during pregnancy are less likely to have Cesarean Section.

"The thinking was that exercise releases norepinephrine in the body, which is a chemical that can stimulate contractions of the uterus, and thus lead to preterm birth," explained Vincenzo Berghella, M.D., Director of Maternal Fetal Medicine and Professor at the Sidney Kimmel Medical College at Thomas Jefferson University and senior author of the study, in a statement. "But numerous studies including this new meta-analysis, have since shown that exercise does not harm the baby, and can have benefits for the mom and baby."

For the new study, researchers collected data from nine randomized controlled studies involving 2,059 pregnant women. In these studies, the participants were divided into two groups. The first group, which consisted of 1,022 women, exercised 35-90 minutes 3-4 times per week for 10 weeks or up until their delivery, while the remaining 1,037 women did not exercise at all.

All the women participating in the studies are healthy, have normal weight and no conditions preventing them from exercising. Additionally, all participants were only carrying a single baby.

Contrary to popular belief, the researchers discovered no significant increase in preterm birth, or giving birth before 37 weeks, in women who engage in exercise than in those who did not.

Furthermore, researchers also found out that exercising during pregnancy offers some health benefits. Among the women who exercise during their pregnancy, 73 percent experienced vaginal delivery, higher than the 67 percent of non-exercising women who also delivered vaginally. Additionally, exercising women have lower incidence of C-section, about 17 percent, while non-exercising women have 22 percent incidence of C-section.

The researchers also noted that exercising during pregnancy might lower the incidence of gestational diabetes, and lower rates of high blood pressure.