Cervical Ripening: Are Double-Balloon Catheters Effective?

In a new study to help determine the optimal method for changing the cervical status from unfavorable to favorable, researchers found that use of a double-balloon catheter for preinduction cervical ripening leads to more vaginal births within 24 hours than does a prostaglandin vaginal insert.¹ Data comparing sustained-release pessaries with mechanical methods are scarce and, according to the study authors, their results further support the potential advantages of mechanical methods of preinduction cervical ripening over pharmacological agents.

Women with a single gestation with vertex presentation, a Bishop score of 6 or lower, intact membranes, and a gestational age of 34 weeks or more were randomly assigned to preinduction cervical ripening with either a double-balloon catheter or a 10-mg controlled-release dinoprostone vaginal insert. After placement, the double-balloon device was left in place for 12 hours. The vaginal insert, placed high in the vaginal fornix, was placed for a maximum of 24 hours. If needed, a standard dose of oxytocin was given to patients not in labor soon after removal of the catheter or 1 hour after completion of the 24-hour dosing period for the dinoprostone insert. Vaginal delivery within 24 hours of initiation of cervical ripening was the primary outcome measure.

Study participants included 105 women in the double-balloon catheter group and 103 women in the dinoprostone vaginal insert group. Seventy-two women (68.6%) in the catheter group, compared with 51 women (49.5%) in the insert group, achieved vaginal delivery within 24 hours-a statistically significant difference. Another significant finding was that more women in the catheter group than in the insert group required oxytocin (90 [85.7%] vs 56 [54.4%], respectively). In addition, 10 cases (9.7%) of uterine hypertonus/tachysystole occurred in the vaginal insert group, compared with no cases in the catheter group.

Based on these findings, the study authors refute the idea that a regimen that allows more time for cervical ripening unavoidably translates into a lower percentage of vaginal deliveries within 24 hours. According to the authors, the increased rate of use of oxytocin in the catheter group reflects the different nature of ripening agents rather than a misuse of oxytocin augmentation that ultimately affects the primary outcome.

Pertinent Points:
- Use of a double-balloon catheter for preinduction cervical ripening was associated with higher rates of vaginal delivery within 24 hours than was a dinoprostone vaginal insert.
- This new evidence is highly relevant to clinical practice because prostaglandins are the main induction method currently recommended to authoritative guidelines for labor induction, according to the study authors.

References:

1. Cromi A, Ghezzi F, Uccella S, et al. A randomized trial of preinduction cervical ripening: dinoprostone vaginal insert versus double-balloon catheter. Am J Obstet Gynecol. 2012;207:125.e1-7.