Outpatient Foley Catheter for Induction of Labor in Nulliparous Women: A Randomized Controlled Trial.

Objective: To assess whether outpatient cervical ripening with a transcervical Foley catheter in nulliparous women undergoing elective labor induction shortens the time from admission to delivery.
Methods: We performed a randomized controlled trial of patients with singleton pregnancies undergoing elective labor induction at 39 weeks of gestation or more with a modified Bishop score less than 5. Women were randomized 1:1 to outpatient or inpatient transcervical Foley. In the outpatient group, the Foley was inserted the day before admission for scheduled induction; insertion was performed at scheduled admission in the inpatient group. The primary outcome was duration of time from admission to the labor and delivery unit to delivery. With 80% power and a two-sided α of 0.05, a sample size of 126 was estimated to detect at least a 5-hour mean difference in time from admission to delivery between groups from a baseline duration of 19±10 hours.
Results: From May 2018 to October 2019, 126 women were randomized, 63 in each group. Baseline characteristics were balanced between groups, except that body mass index (31±5.4 vs 34±7.5, P=.01) and group B streptococcus colonization (31% vs 54%, P=.01) were lower in the outpatient group. The time from admission to delivery was shorter in the outpatient group (17.4±7.4 vs 21.7±9.1 hours, P<.01, mean difference 4.3 hours, 95% CI 1.3-7.2). Admissions before scheduled induction were higher in the outpatient group (22% vs 5%, relative risk [RR] 4.7, 95% CI 1.4-15.4, P<.01), as was median modified Bishop score on admission (3 vs 1, P<.01). Cesarean delivery (24% vs 32%, RR 0.8, 95% CI 0.4-1.3, P=.32) and chorioamnionitis (22% vs 13%, RR 1.8, 95% CI 0.8-3.9, P=.16) were not significantly different between groups.
Conclusion: In nulliparous patients undergoing elective labor induction at term, outpatient cervical ripening with a transcervical Foley catheter reduced the time from admission to delivery.
Clincal Trial Registration: ClinicalTrials.gov, NCT03472937.