Comparing transcervical balloon with osmotic dilators for cervical preparation prior to procedural abortion: A noninferiority randomized trial.

Abstract

Objectives: This study aimed to compare cervical preparation with transcervical balloon to osmotic dilators for second-trimester procedural abortions.

Study design: We performed an unblinded, randomized, noninferiority trial of people undergoing second-trimester procedural abortion at 18 + 0 to 23 + 6 weeks' gestation. We randomized participants to either overnight osmotic dilators (Dilapan-S) or transcervical balloon (Foley). Both groups received overnight mifepristone and preprocedural misoprostol. We powered the study on mean difference in procedure duration, a noninferiority limit of 5 minutes. We compared preprocedure cervical dilation and the need for additional dilation and, using a 100-point visual analog scale, measured physician satisfaction and ease of procedure, and participant pain and satisfaction.

Results: We recruited 32 participants at a single academic center. Although procedure time (minutes) was similar (balloon: 22.6 ± 8.9 vs Dilapan-S: 22.4 ± 12.8, p = 0.96), noninferiority was not met (mean difference, 0.2 minutes; 95% CI, -7.8 to 8.2). Cervical dilation >2 cm was more likely after Dilapan-S (100% vs 62.5%, p = 0.02). Placement was well tolerated with similar time (minutes) for insertion (balloon: 4.8 ± 1.0, Dilapan-S: 5.1 ± 2.3, p = 0.64) and maximum pain (median) with insertion (balloon 39 [5-78], Dilapan-S: 39 [0-100], p = 0.92). Pain immediately postinsertion was higher for Dilapan-S (33 [0-100] vs 18 [0-50], p = 0.046) and similar for maximum pain overnight, participant satisfaction, and likelihood to recommend. Complications were minor and similar between groups (p = 0.60).

Conclusion: While significantly more people with transcervical balloon required mechanical dilation, the difference in operative time was clinically negligible. The transcervical balloon was well tolerated and acceptable by participants.

Implications: Clinicians experienced in mechanical dilation may consider a transcervical balloon as a lower-cost tool for second-trimester abortion cervical preparation.

Clinical trial registration: ClinicalTrials.gov: NCT05099991.