Purpose of review
Recent evidence supports elective induction of labor after 39 weeks; however, labor induction in patients with an unfavorable cervix, a Bishop score less than 6, may take several days. In this review, we focus on the efficacy and safety of methods of labor induction for the unfavorable cervix.
Recent evidence on the use of mechanical cervical preparation with transcervical balloons suggests balloons are the most effective option for decreasing time to delivery in the nulliparous patient. Single and double balloons are equally effective, with a volume of more 30 ml being more effective. The addition of misoprostol or oxytocin concurrently with a balloon further expedites time to delivery.
Mechanical dilation should be considered when available and technically possible for labor induction in patients with an unfavorable cervix. Misoprostol is an effective adjunct to trans-cervical balloons, further decreasing time to delivery as compared with balloon alone. When misoprostol is contraindicated, oxytocin is a safe, effective, alternative adjunct to trans-cervical balloons. More research is needed to evaluate safe outpatient options, induction methods in the setting of prior cesarean with an unfavorable cervix, and to directly compare misoprostol with oxytocin as adjuncts to transcervical balloons.