Isosorbide mononitrate vaginal gel versus misoprostol vaginal gel versus Dilapan-S for cervical ripening before first trimester curettage.

Objective: To compare the efficacy and safety of vaginal applications of three different principles of cervical priming prior to first trimester curettage, isosorbide mononitrate (ISMN), misoprostol and Dilapan-S, a hygroscopical cervical dilator.

Study Design: Pregnant women with missed abortion between 6 and 12 gestational weeks were included and randomly assigned to receive either 80 mg ISMN vaginal gel (group 1) or 200 microg of misoprostol vaginal gel (group 2) or Dilapan-S, a hygroscopical cervical dilator (group 3), for cervical ripening before curettage. Outcome parameters were cervical dilation at the time of operation and maximum dilation reached with Hegar's dilator and the degree of difficulty in mechanical dilation as well as safety and side effects of the preparations.

Results: Sixty-five pregnant women with missed abortion were included and assigned to the three study groups (n=22 for group 1, n=22 for group 2, n=21 for group 3). Misoprostol vaginal gel and Dilapan-S were significantly more effective than ISMN vaginal gel in cervical dilation reached with priming (p<0.005 and p<0.005) and in the degree of difficulty in cervical dilation assessed by the surgeon (p<0.001 and p<0.01). Mild discomfort was indicated by all patients after Dilapan insertion, whereas no patient complained about discomfort after misoprostol or ISMN insertion (p<0001). Three patients suffered from mild hypotension and headache after ISMN treatment, and two had increased vaginal bleeding due to uterine atony during surgery (p<0.05).

Conclusion: A vaginal gel of ISMN is less effective for cervical ripening prior to first trimester curettage compared to misoprostol vaginal gel or Dilapan-S. The latter could be an effective and safe alternative to prostaglandin priming avoiding preoperative contractions caused by prostaglandin preparations.