Induction of labor with cervical ripening balloon associated with oral misoprostol: an observational study comparing sequential and concurrent administration.

Background: The association of cervical ripening balloons (CRB) and misoprostol for induction of labor (IoL) is frequently used, although there is poor evidence about the optimal timing and protocol for their combination. The aim of this study was to compare a concurrent and a sequential scheme for administration of oral misoprostol in association with CRB, in terms of mode and timing of delivery and rate of adverse events.

Methods: This was an observational study comparing two consecutive cohorts of women with unfavorable cervix undergoing IoL by means of double-balloon CRB combined with oral misoprostol, with either a sequential scheme (retrospective cohort, N.=36) or a concurrent administration (prospective cohort, N.=30). The primary outcome was the rate of vaginal delivery (VD); secondary outcomes included the interval of time to labor and delivery and the incidence of maternal or perinatal complications.

Results: The concurrent administration of misoprostol combined with CRB resulted in a similar rate of VD compared to the sequential scheme (63.9% vs. 76.7%, P=0.29). Both time to active labor (32.7±10.9 vs. 21.8±9.6 hours, P=0.001) and to vaginal delivery (34.0±12.6 vs. 25.3±10.2 hours, P=0.016) were shorter for concurrent misoprostol administration, resulting in a higher rate of VD within 24 hours (13.9% vs. 43.3%, P=0.01). The rate of maternal and perinatal adverse outcomes did not differ significantly between the two groups.

Conclusions: Concurrent use of CRB and oral misoprostol might be preferable due to similar results in terms of mode of delivery, achieved in a shorter time with no increase in complications; further studies on larger populations will be needed to verify potential differences in CS rates and rare adverse events.