Maternal obesity and contraction strength in the first stage of labor.

Abstract

The purpose of this study was to determine whether maternal obesity is associated with cesarean delivery and decreased contraction strength in the first stage of labor. We studied a retrospective cohort of women who delivered within a single healthcare system from 2007-2009; we included 5410 women with an intrauterine pressure catheter during the last 2 hours of the first stage of labor and who either had a vaginal delivery or cesarean delivery for dystocia. Logistic regression was used to determine how body mass index was associated with cesarean delivery or mean Montevideo units of ≥200. Although obese women were at significantly greater odds of cesarean delivery than normal-weight women (odds ratio, 2.4; 95% confidence interval, 1.9-3.1), they were equally able to achieve Montevideo units of ≥200. Among women with a vaginal delivery, obese women had a longer first stage of labor compared with normal-weight women (597 vs 566 min; P = .003). Obese women have longer labors but are equally able to achieve adequate Montevideo units as normal-weight women.