Misoprostol Vaginal Insert Compared With Dinoprostone Vaginal Insert: A Randomized Controlled Trial

OBJECTIVE: To compare the 50-microgram (misoprostol vaginal insert 50) and 100-microgram (misoprostol vaginal insert 100) dose reservoirs of the misoprostol vaginal insert to 10-mg dinoprostone vaginal insert for time to vaginal delivery and rate of cesarean delivery. METHODS: A total of 1,308 women requiring cervical ripening (modified Bishop score less than or equal to 4) before induction of labor were randomly assigned to receive misoprostol vaginal insert 100 (n=428), misoprostol vaginal insert 50 (n=443) or 10-mg dinoprostone vaginal insert (n=436). The primary outcomes were time to vaginal delivery and rate of cesarean births. Safety was also assessed by comparing frequency of adverse events. RESULTS: Median time to vaginal delivery was 1,596, 2,127, and 1,650 minutes for misoprostol vaginal insert 100, misoprostol vaginal insert 50, and dinoprostone vaginal insert, respectively (P=.97 and 0.01 compared with dinoprostone vaginal insert, respectively). Of those who delivered in first admission, cesarean deliveries occurred in 119 of 421 (28.3%), 124 of 429 (28.9%), and 115 of 424 (27.1%) of participants treated with misoprostol vaginal insert 100, misoprostol vaginal insert 50, and dinoprostone vaginal inserts, respectively (relative risk 1.04, 95% confidence interval 0.84–1.30 for misoprostol vaginal insert 100 and relative risk 1.06, 95% confidence interval 0.86–1.32 for misoprostol vaginal insert 50 compared with dinoprostone vaginal insert). Medication-related adverse events included hyperstimulation syndrome in 17 of 428 (4.0%), 6 of 443 (1.4%), and 21 of 436 (4.8%); and nonreassuring fetal heart rate patterns in 63 of 428 (14.7%), 54 of 443 (12.2%), and 67 of 436 (15.4%) of participants treated with the misoprostol vaginal insert 100, misoprostol vaginal insert 50, and dinoprostone vaginal inserts, respectively. CONCLUSION: The misoprostol vaginal insert 100 and the dinoprostone vaginal insert had similar median time intervals to vaginal delivery, whereas the misoprostol vaginal insert 50 had a significantly longer time to vaginal delivery. The three products had similar cesarean rates and safety profiles. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov, www.clinicaltrials.gov, NCT00308711 LEVEL OF EVIDENCE: I