Mifepristone vs. osmotic dilator insertion for cervical preparation prior to surgical abortion at 14-16 weeks: a randomized trial.

Background: Cervical preparation is recommended before second-trimester abortion. We investigated the use of a pharmacologic method of preparation, mifepristone, as compared to osmotic dilators for surgical abortions at 14-16 weeks.

Study Design: This was a randomized, parallel-group study with concealed allocation. Women were allocated to receive osmotic dilators or mifepristone 200 mg orally 24 h prior to abortion. The study population was 50 women seeking surgical abortion at 14-16 menstrual weeks in a hospital-based abortion service. The primary outcome was the length of time to perform the procedure; the study had 80% power to detect a difference of more than 3 min in procedure time. Secondary outcomes included cervical dilation, side effects and acceptability.

Results: The mean abortion time for the osmotic dilator group was 8.00 min [95% confidence interval (CI) 6.75-11.47], and that for the mifepristone group was 9.87 min (95% CI 8.93-11.36). Side effects of pain were more common in the osmotic dilator group.

Conclusion: Mifepristone did not increase the time for abortion by more than the prespecified margin (3 min). Women preferred mifepristone to osmotic dilators.