(236) Impact of outpatient cervical ripening prior to term induction of labor - prospective randomized trial

Objective: To determine if there is an advantage to preadmission outpatient cervical ripening with a transcervical (Foley) balloon (FB) prior to induction.

Study Design: Prospective randomized trial of pregnant persons ≥ 39 wks scheduled for induction requiring cervical ripening (Bishop score < 6). Those with maternal/fetal complications, amniotic fluid abnormalities, and/or non-reassuring non stress test (NST) were excluded. Participants were randomized to FB placement as outpatient 12 hours (h) prior to induction admission (Outpt) or on admission (Inpt). Labor management was otherwise routine. Analysis was intention-to-treat (ITT). Planned sample size was 200; study was ended at 140 due to slow enrollment.

Results: 140 women were randomized from 11/2021-3/2024, 73 Outpt and 67 Inpt. Baseline characteristics between groups were similar (Table 1) with most inductions elective (95%). In the Outpt group, FB placement was successful in 65/73 (84%); 3/65 (4.6%) required immediate admission due to abnormal post-FB NST (2) or labor (1). Of 8 unsuccessful Outpt FB placements, 5 had bleeding or membrane rupture and 3 could not be placed. In the Inpt group, 59/67 (88.1%) had successful FB placement on admission; 5 no longer required cervical ripening and for 3 the FB could not be placed. In ITT analysis, time from FB placement to delivery was longer in Outpt group (28.5 vs 20.2 h, p< 0.001). There was no difference in use of other induction agents, mode of delivery, infection, neonatal outcomes, median maternal total length of stay (65.4 vs 65.3 h, p=0.762), admission to delivery time (20.9 vs 21.4 h, p=0.507), or total inpatient charges ($36,843 vs $36,269, p=0.899) (Tables 2-4). When comparing outcomes for those that actually received the FB as planned (62 Outpt, 62 Inpt), there was a trend towards a decrease in median time from admission to delivery (18.6 vs 22.8 h, p=0.054) but no difference in maternal length of stay or cost.

Conclusion: Outpatient cervical ripening with transcervical balloon prior to term induction is safe and feasible but may not be associated with clinical benefit or cost savings.