30 mL Single- versus 80 mL double-balloon catheter for pre-induction cervical ripening: a randomized controlled trial

Abstract

Objective: To compare the efficacy of an 80 mL double-balloon catheter versus a 30 mL single-balloon catheter for pre-induction cervical ripening.

Methods: We performed a randomized controlled trial of women ≥18 years with a singleton, vertex pregnancy, a reactive non-stress test, and a Bishop score ≤5 comparing an 80 mL double- versus a 30 mL single-balloon catheters for cervical ripening. Women were randomly assigned to the two catheter types, stratified 1:1 by nulliparity or multiparity. The primary outcome was achieving a Bishop score ≥6 at the time of catheter expulsion or removal assessed by chi-squared, stratified by parity.

Results: A total of 98 women were included in the analysis (50 in the 80 mL double and 48 in the 30 mL single-balloon catheter groups). Among nulliparous women, a greater proportion of those randomized to the 80 mL double achieved a Bishop score ≥6 at time of catheter removal (88.0% versus 28.0%; p ≤ 0.001) and delivered vaginally (60.0% versus 32.0%; p = 0.047) compared to those with the 30 mL single-balloon catheter. We found no difference by catheter type in achieving a Bishop score ≥6 or vaginal delivery among multiparous women.

Conclusions: These findings suggest the 80 mL double-balloon catheter is more effective than the 30 mL single-balloon catheter for pre-induction cervical ripening and achieving a vaginal delivery in nulliparous women.

• Balloon catheters
• cervical ripening
• induction of labor

Acknowledgements

The authors thank the University of Washington residents, Labor & Delivery nurses, Kathy O’Connell, Zane Brown.

Declaration of interest

All authors report no declarations of interest. We confirm this study was not funded by Cook and none of the authors have any relationship with this company.