Combining pharmacologic agents with mechanical ripening achieves the shortest time to labor; however, there is no clear evidence on route of drug administration. Buccal administration of misoprostol has shown greater patient acceptance but remains understudied.

This study aimed to evaluate the difference in time to delivery between buccal and vaginal administration of misoprostol along with a Foley catheter for induction of labor.

The BEGIN trial (buccal vs vaginal misoprostol combined with Foley catheter for cervical ripening at term) was an institutional review board–approved, randomized clinical trial conducted from June 2019 to January 2020 comparing identical doses (25 μg) of buccal misoprostol and vaginal misoprostol along with a Foley catheter for induction of labor. Randomization was stratified by parity. Labor management was standardized among participants. Individuals undergoing induction of labor at ≥37 weeks with a singleton gestation and needing cervical ripening were included. Our primary outcome was time to delivery. Kruskal-Wallis, Pearson chi-squared, and Cox survival analyses with intent-to-treat principles were performed. A sample size of 216 was planned to detect a 4-hour reduction in delivery time.

A total of 215 women (108 in the buccal drug administration group and 107 in the vaginal drug administration group) were randomized. The vaginal route of drug administration achieved a faster median time to delivery than the buccal route of drug administration (19.7 hours in the vaginal route vs 24.1 hours in the buccal route; P<.001). A greater percentage of women in the vaginal drug administration group delivered within 24 hours compared with the buccal drug administration group (65% vs 49%; P=.02). There was no difference in the cesarean delivery rate between the 2 groups (17% in the vaginal drug administration group vs 21% in the buccal drug administration group; P=.6). Individuals who received vaginal misoprostol with Foley catheter delivered 2 times faster than women who received buccal misoprostol with Foley catheter after censoring for cesarean delivery and adjusting for parity (hazard ratio, 2.13; 95% confidence interval, 1.44–3.17). There was no significant difference in maternal and neonatal outcomes.

We found that vaginal administration of misoprostol was superior to buccal administration of misoprostol along with a Foley catheter for induction of labor. Furthermore, vaginal administration of misoprostol resulted in twice the chance of delivering earlier compared with buccal administration of misoprostol with no difference in cesarean delivery rates. Therefore, the vaginal route of administration of misoprostol should be preferred among individuals undergoing a combined pharmacologic and mechanical induction.