Cervical ripening with a double balloon device for 6 h in patients with a long cervix: Secondary analysis of a randomized controlled trial

Abstract

Objective

To examine whether cervical ripening with a double balloon device for 6 h is as effective as 12 h in patients with a cervical length ≥ 30 mm measured on transvaginal ultrasound before induction of labor, and to determine whether patients with a long cervix need to have the balloon placed for a longer time.

Methods

This is a secondary analysis of data from a randomized controlled trial that compared maternal and neonatal outcomes between women undergoing cervical ripening with a double balloon device for 6 h (study group) versus 12 h (control group). In this secondary analysis, we included only patients who had cervical length ≥ 30 mm measured on transvaginal ultrasound on admission. Our primary outcome was a Bishop score change after removal of the device. Secondary outcomes included insertion to delivery interval, mode of delivery, and oxytocin infusion duration.

Results

Sixty-seven women met the inclusion criteria and were included in the analysis: 33 in the 6-h group and 34 in the 12-h group. Maternal characteristics were similar between both groups. Bishop score difference between the preinsertion and the postremoval scores were similar in the two groups (2.67 ± 1.8 vs. 2.53 ± 1.69, P = 0.76), while insertion to delivery time was 10 h shorter in the 6-h group (20.95 vs. 31.21, P = 0.02; mean difference, −10.26 [95% CI, −19.0 to −1.51]). The other secondary outcomes remained similar in both groups.

Conclusion

In women undergoing induction of labor who have a cervical length ≥ 30 mm measured on admission transvaginal ultrasound, removing a double balloon device after 6 h achieved similar Bishop score changes as removal after 12 h, but significantly reduced the time to delivery.

Registration at Clinical Trials

https://classic.clinicaltrials.gov/ct2/show/NCT03045939.