1. Compared to sequential use, simultaneous use of oxytocin and a foley balloon for cervical ripening was associated with a shorter time to delivery.
2. There was no difference in the rate of cesarean delivery or maternal/perinatal complications between the two groups.
Evidence Rating Level: 1 (Excellent)
Study Rundown: Roughly one in five births today begin with induction of labor in which the medication oxytocin is used to stimulate uterine contractions in women who do not naturally begin contracting on their own. If the cervix is determined to be unfavorable based on Bishop’s score, cervical softening or ripening is used to prepare the cervix. There are numerous methods of cervical ripening, including the use of topical prostaglandins. One method involves passing a foley catheter balloon through the cervix, inflating it in the uterus and taping it to the patient’s leg to mimic the pressure applied to the cervix by the fetal vertex and thus promote cervical ripening. There’s a paucity of research on the optimal timing of the two interventions; one randomized controlled trial compared sequential versus simultaneous use of the two methods but wasn’t powered to detect a difference in time to delivery or to stratify by parity. In this study, researchers measured time to delivery in nulliparous women who had been randomized to either simultaneous or sequential use of a Foley balloon and intravenous oxytocin.
The simultaneous use of oxytocin and Foley balloon was associated with a nearly 3 hour shorter time to delivery than sequential use of the 2 methods. Strengths included sample size (n>80 in both intervention arms) and rigorous randomized trial. Limitations include lack of provider blinding to the intervention group, which was not practical, and single center study design. Future investigations could blind providers to the cervical ripening randomization assignment in a multi-center trial design; replication of results of the present work would lend credence to the findings presented here.
In-Depth [randomized trial]: Nulliparous women presenting for induction of labor with unfavorable cervices were randomized to either simultaneous oxytocin and Foley balloon induction (n = 82) or sequential Foley balloon followed by oxytocin induction (n = 84). The primary outcome was time from induction to delivery. Secondary outcomes included mode of delivery, estimated blood loss, postpartum hemorrhage, chorioamnionitis, and a composite neonatal morbidity outcome. Analysis was performed by the intention-to-treat analysis principle.
Compared to sequential ripening, women who received simultaneous cervical ripening with oxytocin and foley balloon achieved delivery earlier (15.9 vs. 18.9 hours, p < 0.01). Results were unchanged cesarean deliveries were excluded, with a shorter time to delivery in the simultaneous compared to sequential group (14.8 vs. 17.6 hours, p = 0.02). There was no difference in the rate of cesarean delivery between the two groups, although more cesareans were performed due to non-reassuring fetal heart tracings in the simultaneous group (29% vs. 3%, p = 0.004).
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