Exercise during Pregnancy and Risk of Late Preterm Birth, Cesarean Delivery, and Hospitalizations

Background: Federal physical activity guidelines recommend at least 150minutes of moderate-intensity exercise per week during pregnancy. We studied whether regular exercise during pregnancy is associated with preterm birth, cesarean delivery, and hospitalization during pregnancy. Methods: Self-reported weekly exercise was ascertained in 3,006 women during the third trimester of pregnancy. Using multivariable logistic regression, we report the relationship between regular exercise (≥150min/wk) and late preterm birth, cesarean delivery, and hospitalization during pregnancy, controlling for age, race, marital status, education, poverty status, prepregnancy body mass index weight category, gestational weight gain, and prepregnancy diabetes or hypertension. Results: Nearly one third of women reported meeting current federal physical activity recommendations during pregnancy. Five percent had late preterm birth, 29% had cesarean deliveries, and 20% reported hospitalization during pregnancy. In multivariable analysis, regular exercise during pregnancy was not associated with late preterm birth or hospitalization during pregnancy. Physical activity of 150 or more minutes per week was associated with reduced odds of cesarean delivery compared with less than 60minutes per week, but the finding was not significant (adjusted odds ratio, 0.86; 95% confidence interval, 0.69-1.07). Conclusion: In the First Baby Study, physical activity was not associated with late preterm birth or hospitalizations, and may be associated with decreased odds of cesarean delivery.