Interruption of nonviable pregnancies of 24–28 weeks' gestation using medical methods

The need to interrupt a pregnancy between 24 and 28 weeks of gestation is uncommon and is typically due to fetal demise or lethal anomalies. Nonetheless, treatment options become more limited at these gestations, when access to surgical methods may not be available in many circumstances. The efficacy of misoprostol with or without mifepristone has been well studied in the first and earlier second trimesters of pregnancy, but its use beyond 24 weeks' gestation is less well described. This document attempts to synthesize the existing evidence for the use of misoprostol with or without mifepristone to induce labor for nonviable pregnancies at gestations of 24–28 weeks. The composite evidence suggests that a regimen combining mifepristone and misoprostol may shorten the time to expulsion, though the overall success rates are similar to those seen with misoprostol-only regimens.