Intracervical Foley catheter with and without oxytocin for labor induction with Bishop score ≤3: a secondary analysis

Abstract

Background: The combination method for cervical ripening with a Foley catheter and concurrent oxytocin administration has been shown to reduce the total time from induction to delivery when compared with a Foley catheter only in patients with an unfavorable cervix (Bishop score of <6). It is unclear if this is still effective for patients with a less favorable cervix as indicated by a Bishop score of ≤3.

Objective: This study aimed to determine if inducing labor with a Foley catheter and concurrent oxytocin administration reduced the total time from induction to delivery in subjects with a Bishop score of ≤3 compared with those who only received a Foley catheter without oxytocin for cervical ripening.

Study design: This was a secondary analysis of a randomized, multicenter trial of patients with a live singleton pregnancy at ≥24 weeks' gestation undergoing labor induction with a Foley catheter and a Bishop score of <6. This analysis included patients with a Bishop score of ≤3. Exclusions included >1 cesarean delivery, unexplained bleeding, nonreassuring fetal tracing, major fetal anomalies, or other contraindications for vaginal delivery. The subjects were randomized to receive an intracervical Foley catheter only or with concurrent oxytocin infusion. The primary outcome for this analysis was the time from induction to delivery. Secondary outcomes included delivery at ≤12 hours, time to delivery ≤24 hours, cesarean delivery, total time of oxytocin infusion, need for additional ripening agents, postpartum hemorrhage, chorioamnionitis, and neonatal intensive care unit admission.

Results: A total of 322 patients were enrolled in the primary trial; 151 subjects had an initial Bishop score of ≤3 and were included in the secondary analysis (n=77 for Foley catheter with oxytocin and n=74 for the Foley catheter only). The demographics were similar in both groups. Those with a Bishop score of ≤3 who received a Foley catheter with concurrent oxytocin administration had a shorter time from induction to delivery than those patients who received a Foley catheter only for cervical ripening (21.3 vs 27 hours; P=.005). The group with a Foley catheter and oxytocin administered concurrently also had a shorter time from induction to delivery after adjusting for body mass index, parity status, and first Bishop score (21.5 vs 26.7 hours; P=.007). They also were more likely to deliver within 24 hours (74% vs 46%; P=.001) and not to require additional ripening agents (4% vs 15%; P=.04). Patients with the Foley catheter only method were more likely to receive additional ripening agents, but had fewer hours of oxytocin infusion (19.1 vs 12.4 hours; P<.001). There was no difference in the rate of delivery at ≤12 hours, cesarean delivery, postpartum hemorrhage, chorioamnionitis, and neonatal intensive care unit admission.

Conclusion: Concurrent Foley catheter and oxytocin infusion significantly reduced the time from induction to delivery in patients with a Bishop score of ≤3 when compared with a Foley catheter only, particularly in multiparous patients.

Trial registration: ClinicalTrials.gov NCT02273115.

Keywords: dilation; ripening; unfavorable.