Can isosorbide mononitrate be useful in second trimester termination of pregnancies?

Isosorbide mononitrate (IMN) administration is thought to enhance in the cervical ripening process. We sought to identify the clinical usefulness and safety of IMN administration for shortening the time to termination of the second trimester pregnancy procedures when used in addition to misoprostol. Women were randomly selected to receive either the standard misoprostol treatment (control group) or, additionally, receive vaginally IMN as well as the misoprostol treatment. The mean induction to complete abortion interval was 20.4 h [95% confidence interval (CI)=16.63-24.17] in the misoprostol group compared with 12.4 h (95% CI=10.33-14.47) in the misoprostol plus IMN group. This difference was statistically significant (p<.05). In the subgroups of nulliparas and multiparas, the shortening effect of the IMN was also statistically significant. A net benefit after the combined use of IMN and misoprostol was noted. Therefore, we believe that IMN has a clinical role in the ripening process.