Objective: The aim of our study was to determine whether the combination of mifepristone and the osmotic dilator Dilapan-S improves the labor induction outcomes as compared to Dilapan-S alone.
Methods: This prospective comparative study included 127 eligible women, of whom 58 underwent cervical ripening with Dilapan-S (12-h exposure, the control group) and 69 with Dilapan-S, with a concurrent pretreatment of 200 mg oral mifepristone (the study group), 8 h before Dilapan-S insertion.
Results: The vaginal delivery rate in the control group and the study group was 60.3 and 76.8% (p = .045), respectively; the induction to delivery interval was 22.74 ± 3.01 h and 19,890 ± 2.42 h (p < .001), respectively; and the number of births within 24 h was 43.1 and 73.9% (p < .001), respectively. There was no difference in the rate of failed labor induction (6.9 versus 8.7%, p = .939). The Bishop's score improved significantly after the combined treatment as compared to with Dilapan alone (3.10 ± 0.58 versus 4.03 ± 1.35, p < .001). Moreover, in the study group, labor started earlier and proceeded faster with a lower additional oxytocin usage for labor induction or augmentation. There were no differences in the operative delivery rate and the perinatal outcomes. There were no adverse side effects of both mifepristone and Dilapan-S.
Conclusion: Our study is the first one to show that in comparison to labor induction using only osmotic dilators Dilapan-S, the combination of mifepristone and Dilapan-S is more efficient in terms of improving cervical ripening and vaginal delivery rate and reducing labor duration and frequency of oxytocin augmentation. The results revealed that this combined method is safe and has no immediate adverse effects on newborns. More studies are needed to evaluate what clinical cases are the most appropriate for the application of this combined method, considering the parity, degree of cervical ripening, and indication for labor induction.
Keywords: Cervical ripening; Dilapan-S; induction of labor; maternal and neonatal outcomes; mifepristone.