Cervical change times during induction in nulliparas using vaginal or buccal misoprostol.

AIM: To determine if the time to cervical change and time to active labor were different when misoprostol was administered by a vaginal or buccal route for cervical ripening in nulliparas undergoing labor induction at term. METHODS: This was a secondary analysis of nulliparous participants in the IMPROVE Study-A comparison of vaginal versus buccal misoprostol for cervical ripening for labor induction at term: a triple-masked randomized controlled trial (NCT02408315). The parent study was a non-inferiority randomized controlled trial in which patients beginning induction with a modified Bishop score ≤6 received either vaginal or buccal misoprostol and simultaneous placebo via the opposite route. The primary outcome of the parent study was time to delivery. Primary outcomes for this secondary analysis were the time to active labor (at least 6 cm dilated) and time to change in cervical dilation. Kaplan-Meier analysis was used to compare routes for time to active labor and multistate Markov modeling was used to compare sojourn times at each cervical dilation. RESULTS: Of the 300 participants enrolled in the parent trial, 124 (41.3%) were nulliparous; 59 (47.6%) nulliparous participants underwent induction with vaginal misoprostol and 65 (52.4%) received buccal dosing. Nulliparas receiving vaginal dosing required fewer doses of misoprostol to reach active labor (median 2 vs 3, p = .003). However, this did not result in shorter time to active labor (median vaginal 23.1 h, 95% CI = [21.6, 27.2 h]; buccal 25.6 h [21.5, 29.3 h], p = .45) or higher rate of vaginal delivery within 24 h; (33.9% vs 35.4%, p = .86). There was also no significant difference in time to active labor after adjusting for covariates (adjusted HR for dose route (buccal vs vaginal) = 0.91 [0.61, 1.36], p = .649). Among people that delivered vaginally, the mean sojourn times, measuring cervical dilation state change, were not significantly different, with mean duration to active labor of 20.5 [17.6, 24.5] h for buccal and 21.8 [17.7, 28.2] h for vaginal dosing (p = .092). Satisfaction and preference for dosing routes were not different between groups. CONCLUSION: Buccal and vaginal dosing of misoprostol for cervical ripening in nulliparas appear to have similar times to active labor and progression of cervical change during ripening.

A comparison of vaginal versus buccal misoprostol for cervical ripening in women for labor induction at term (the IMPROVE trial): a triple-masked randomized controlled trial.

BACKGROUND: Cervical ripening is commonly needed for labor induction. Finding an optimal route of misoprostol dosing for efficacy, safety, and patient satisfaction is important and not well studied for the buccal route. OBJECTIVE: To compare the efficacy and safety of vaginal and buccal misoprostol for women undergoing labor induction at term. STUDY DESIGN: The IMPROVE trial was an institutional review board-approved, triple-masked, placebo-controlled randomized noninferiority trial for women undergoing labor induction at term with a Bishop score ≤6. Enrolled women received 25 mcg (first dose), then 50 mcg (subsequent doses) of misoprostol by assigned route (vaginal or buccal) and a matching placebo tablet by the opposite route. The primary outcomes were time to delivery and the rate of cesarean delivery performed urgently for fetal nonreassurance. A sample size of 300 was planned to test the noninferiority hypothesis. RESULTS: The trial enrolled 319 women, with 300 available for analysis, 152 in the vaginal misoprostol group and 148 in the buccal. Groups had similar baseline characteristics. We were unable to demonstrate noninferiority. The time to vaginal delivery was lower for the vaginal misoprostol group (median [95% confidence interval] in hours: vaginal: 20.1 [18.2, 22.8] vs buccal: 28.1 [24.1, 31.4], log-rank test P = .006, Pnoninferiority = .663). The rate of cesarean deliveries for nonreassuring fetal status was 3.3% for the vaginal misoprostol group and 9.5% for the buccal misoprostol group (P = .033). The rate of vaginal delivery in <24 hours was higher in the vaginal group (58.6% vs 39.2%, P = .001). CONCLUSION: We were unable to demonstrate noninferiority. In leading to a higher rate of vaginal deliveries, more rapid vaginal delivery, and fewer cesareans for fetal issues, vaginal misoprostol may be superior to buccal misoprostol for cervical ripening at term.