Objective: To assess the association between participation in aerobic exercise during the first two trimesters of pregnancy and type of delivery in nulliparous women.
Design: Nonexperimental, retrospective.
Setting: A large metropolitan area in the southwestern United States.
Participants: 137 nulliparous women.
Outcome measures: Method of delivery.
Results: An unadjusted odds ratio showed that sedentary women (n = 93) were 2.05 times more likely to deliver via cesarean section than active women (n = 44), but this relationship was not statistically significant. Through logistic regression analysis with control for the mother's prepregnancy exercise program, age, use of epidural anesthesia, change in prepregnancy to delivery body mass index, labor length, whether labor was induced, and the hospital of birth, the odds of cesarean delivery were found to be 4.5 times greater for sedentary women than for active women.
Conclusion: Regular participation in physical activity during the first two trimesters of pregnancy may be associated with reduced risk for cesarean delivery in nulliparous women.