Comparison of the efficacy and safety of misoprostol and a Cook cervical ripening double-balloon catheter, alone and in combination, for cervical ripening and induction of labor.

AIM: This retrospective cohort study evaluated the associations of misoprostol alone, a Cook cervical ripening double-balloon catheter alone, and their combination for cervical ripening and labor induction in women with an unfavorable cervix.

METHODS

A total of 200 women with singleton term pregnancies, Bishop score ≤6, who underwent labor induction (April 2023-April 2024) were assigned to oral misoprostol alone (n = 80), a Cook cervical ripening double-balloon catheter alone (n = 60), or sequential misoprostol followed by the Cook double-balloon catheter (n = 60). The retrospective, non-randomized design precludes causal inference. The primary outcome was the 24-h change in Bishop score. Secondary outcomes included induction-to-delivery interval, vaginal delivery rate, and adverse events. Multivariable regression and propensity score matching were used to adjust for confounding.

RESULTS

The combination group showed a greater Bishop score increase (mean difference vs. misoprostol: 1.9, 95% CI 1.5-2.3; vs. Cook cervical ripening double-balloon catheter: 2.6, 95% CI 2.2-3.0; both p < 0.001) and a shorter induction-to-delivery interval (median difference vs. misoprostol: -4.7 h, 95% CI -6.0 to -3.5; vs. Cook cervical ripening double-balloon catheter: -4.2 h, 95% CI -5.5 to -3.0). Combination therapy was associated with higher odds of vaginal delivery (vs. misoprostol: aOR 2.45, 95% CI 1.45-4.14; vs. Cook cervical ripening double-balloon catheter: aOR 2.89, 95% CI 1.67-5.01). No statistically significant differences in measured short-term adverse events were observed, but the study was not powered to detect rare safety outcomes (e.g., uterine rupture). The p-value for uterine hyperstimulation (0.074) reflects statistical uncertainty.

CONCLUSION

In this retrospective cohort, the sequential use of oral misoprostol followed by a Cook cervical ripening double-balloon catheter with a Cook cervical ripening double-balloon catheter was associated with more favorable cervical ripening and labor induction outcomes compared with either method alone. Because of the observational design, causality cannot be inferred. These findings suggest that combination therapy may be a reasonable option for appropriately selected patients, but confirmation in randomized controlled trials is needed.