RU-486 has been used in combination with another drug called misoprostol, to terminate pregnancy at an early stage. It is used with women who are no more than 7 weeks pregnant. The drug has 95% effectiveness. About 5% of women using RU-486 in early pregnancies need additional medical intervention because of incomplete abortions. (doctors often intervene at higher rates in cases of natural miscarriages). The side effects with RU-486 are similar to those of a natural miscarriage.