Cervical ripening with Foley catheter balloon: A prospective cohort of 320 women.

Objective: This study evaluates the efficacy and safety of cervical ripening with a Foley catheter balloon in a cohort of women with a medical indication for labor induction.

Methods: In this prospective observational study, we evaluated 320 women with singleton term pregnancies, Bishop's score less than 6, and scheduled cervical ripening with a Foley catheter balloon. The outcomes assessed were: Bishop's score at first re-evaluation 18-24 h later, gain in Bishop's score at first re-evaluation, Bishop's score ≥6 at first re-evaluation, onset of labor in the 24 h after insertion, delivery within 24 h, delivery within 48 h, and failed labor induction. Overall success of cervical ripening was defined as achieving a favorable Bishop's score or onset of labor within 24 h. Adverse events occurring during balloon insertion or until the first re-evaluation were also documented.

Results: At first re-evaluation 18-24 h later, 106 women (33.1%) had a Bishop's score ≥6, and the median gain in Bishop's score was 2. In the first 24 h after balloon insertion, 48 women (15%) went into labor, for an overall success rate of 48.1%. Delivery within 48 h occurred in 214 (66.9%), and failed labor induction in 38 (11.9%). Adverse events were observed in 14 women (4.4%), mainly pain/discomfort, vaginal bleeding, and balloon rupture. All were mild and required no further intervention. The risk of caesarean delivery for failed labor induction was decreased with outpatient cervical ripening (OR 0.39, 95% CI 0.16-0.86), and when an open cervix was present at the start of the process (OR 0.43, 95% CI 0.18-0.97).

Conclusion: Approximately half of women undergoing cervical ripening with a Foley catheter balloon achieve a favorable cervix or onset of labor within 24 h; 67% are delivered within 48 h. Adverse events are rare and mild, requiring no further intervention. Outpatient cervical ripening and an open cervix on admission are associated with higher success rates.