641: High versus low dose oxytocin in lean and obese women: a double-blinded randomized controlled trial

Abstract

Obese women have longer labors and are more likely to require a cesarean delivery. We hypothesized that high dose oxytocin would decrease time to delivery in an obese cohort undergoing an induction of labor. We randomized lean and obese women into four groups: lean women receiving low dose oxytocin, lean women receiving high dose oxytocin, obese women receiving low dose oxytocin and obese women receiving high dose oxytocin. This was a double blinded randomized controlled trial with an intention to treat analysis. We recruited lean and obese women at ≥37weeks gestational age who were undergoing induction of labor. 35 patients in each of the 4 groups were recruited with a total sample size of 140. The lean and obese cohorts were randomized to receive either low or high dose oxytocin infusions. The primary outcome was length of time to delivery defined by number of minutes from induction of labor to delivery. Randomization and provision of study medication was performed by the research pharmacy. Study medication provided by the pharmacy appeared identical per arm. The primary outcome, time to vaginal delivery, was similar between the low and high groups in the lean group (796 (± 411) versus 694 (± 466) minutes, P=0.363) and the obese group (715 (± 497) versus 762 (± 594) minutes, P=0.733). Kaplan-Meier curves between the low and high groups were not significantly different in the lean (P=0.391) and obese (P=0.692) groups. There were 5 (14.29%) cesarean deliveries in the low dose lean group, compared to 2 (5.71%) in the high dose lean group. There were 4 (11.43%) cesarean deliveries in the low dose obese group, compared to 1 (2.86%) in the high dose obese group. There was no difference between the incidence of postpartum hemorrhage for the lean (p = 0.706) and the obese (p = 0.324) groups. There was no difference in mean estimated blood loss for the lean (p = 0.472) and the obese (p = 0.215) groups. There was no difference in time to delivery between the low and high dose oxytocin protocol in either the lean or obese cohort undergoing an induction of labor.View Large Image Figure ViewerDownload Hi-res image Download (PPT)