Objective: To compare the efficacy and safety of a 200-microgram misoprostol vaginal insert with a 10-mg dinoprostone vaginal insert for reducing the time to vaginal delivery.
Methods: In a phase III, double-blind, multicenter study, women being induced with a modified Bishop score of 4 or less were randomly assigned to receive either a 200-microgram misoprostol vaginal insert or a 10-mg dinoprostone vaginal insert. Coprimary end points were time to vaginal delivery and rate of cesarean delivery. Secondary end points included time to any delivery mode, time to onset of active labor, and oxytocin use.
Results: A total of 1,358 women were randomized to receive the 200-microgram misoprostol vaginal insert (n=678) or dinoprostone vaginal insert (n=680). Women receiving the misoprostol vaginal insert had a significantly shorter median time to vaginal delivery compared with patients receiving the dinoprostone vaginal insert (21.5 hours compared with 32.8 hours, P<.001). Cesarean delivery occurred in 26.0% and 27.1% of women receiving the misoprostol vaginal insert and dinoprostone vaginal insert, respectively. A significant reduction in time to any delivery (18.3 hours compared with 27.3 hours), time to onset of active labor (12.1 hours compared with 18.6 hours), and proportion of women requiring predelivery oxytocin (48.1% compared with 74.1%) was observed with the misoprostol vaginal insert compared with dinoprostone vaginal insert (P<.001 for each). Uterine tachysystole requiring intervention occurred in 13.3% and 4.0% of participants receiving the misoprostol vaginal insert and dinoprostone vaginal insert, respectively (P<.001).
Conclusion: Use of a 200-microgram misoprostol vaginal inset significantly reduced times to vaginal delivery and active labor with reduced need for oxytocin compared with the dinoprostone vaginal insert. Cesarean delivery rates were similar with both treatments. Tachysystole was more common in women receiving the 200-microgram misoprostol vaginal insert.
Clinical trial registration: ClinicalTrials.gov, www.clinicaltrials.gov, NCT01127581.
Level of evidence: I.