High-dose vaginal misoprostol versus concentrated oxytocin plus low-dose vaginal misoprostol for midtrimester labor induction: A randomized trial

Abstract

This study was undertaken to compare the efficacy and side effects of a high-dose vaginal misoprostol regimen to concentrated intravenous oxytocin plus low-dose vaginal misoprostol for midtrimester labor induction. Women at 14 to 24 weeks, with obstetric or fetal indications for delivery and no prior cesarean, were randomly assigned to receive either vaginal misoprostol 600 microg x 1, then 400 microg every 4 hours x 5 (group 1) or escalating dose-concentrated oxytocin infusions (277-1667 mU/min) plus vaginal misoprostol 400 microg x 1, then 200 microg every 6 hours x 2, then 100 microg x 1 (group 2). Analysis was by intent to treat. Primary outcomes were live birth rate and induction-to-delivery interval. The intended sample size was 70 women per group; however, the trial was terminated at the initial interim analysis because of a highly significant difference in 1 of the primary study outcomes. Twenty women were assigned to group 1 and 18 were assigned to group 2. Median induction-to-delivery interval was significantly shorter in group 1 (12 hours, range 4-44 hours) versus group 2 (18 hours, range 7-36 hours; P = .01). Induction success rate at 12 hours was significantly higher in group 1 (60%) compared with group 2 (22%, P = .02). No significant difference was noted in the live birth rate between groups 1 and 2 (13%, 0%, P = .16). The incidence of retained placenta requiring curettage, chorioamnionitis, intrapartum fever, nausea, emesis, and diarrhea were similar between both groups. Compared with concentrated oxytocin plus low-dose vaginal misoprostol, high-dose vaginal misoprostol significantly shortens midtrimester labor inductions.