Obstetric outcomes after cervical ripening by multiple doses of vaginal prostaglandin E2

The study was designed to investigate the delivery outcome in women who required vaginal prostaglandin E2 for cervical priming prior to labor induction.

This retrospective cohort study included all singleton term deliveries that required labor induction over a 3-year period. Incidence and indications of obstetric interventions were compared among women who required different doses of vaginal prostaglandin E2 for cervical priming and who had induction by amniotomy and oxytocin infusion.

Of 706 deliveries, 411 had favorable Bishop's scores and no vaginal prostaglandin E2 for cervical priming was required (group A); 268 required one or two doses of vaginal prostaglandin E2 for cervical priming (group B); and 27 required three or more doses (group C). The incidence of cesarean section was significantly higher in group C (48.1%) than in group A (19.0%) and group B (16.4%). The difference remained statistically significant when primiparous and multiparous women were analyzed separately. The risk of obstetric intervention was particularly high in primiparous women in group C (58.8% required emergency cesarean section and 23.5% had instrumental delivery). There was an increased frequency of all major indications for cesarean section in group C.

The risk of emergency cesarean section was higher in women who required more than two doses of vaginal prostaglandin E2 for cervical priming compared to induction by one or two doses of vaginal prostaglandin E2 or by amniotomy and oxytocin infusion. These women should be informed regarding the high risk of intrapartum cesarean section, and the option of alternative methods of induction or elective cesarean section should be made available.