Misoprostol (RU-486) is a prostaglandin medicine used to terminate a pregnancy by starting labor. It is more effective when used in combination with methotrexate or mifepristone than when used alone. This is an unlabeled use of misoprostol. Misoprostol is also used to prevent stomach ulcers (labeled use) and for induction of labor for childbirth (unlabeled use).
Misoprostol may also be used to:
- Complete a spontaneous missed abortion (incomplete miscarriage).
- Start labor in second-trimester abortions.
- Start labor in third-trimester abortions. Third-trimester abortions are not done unless the fetus has died or has severe medical problems and will not survive.
- Dilate the cervix 3 to 4 hours before a surgical abortion procedure.
- Soften the cervix for induction of labor.
- Soften the cervix for special gynecologic tests.
Misoprostol used alone may terminate a pregnancy. But it is more often used with other medicines, such as mifepristone or methotrexate, in first-trimester abortions.
How Well It Works
Misoprostol alone, moistened and used vaginally, is effective in over 90 out of 100 cases in terminating first-trimester pregnancies of less than 8 weeks.
Misoprostol can be given orally, buccally (dissolved between the gums and cheek), or vaginally. Misoprostol is slightly more effective when taken vaginally than when taken by mouth. But many doctors are only giving misoprostol by mouth because of reports of a rare, fatal infection that affected a few women after using vaginal misoprostol. Some studies have shown that taking misoprostol buccally works as well as when it is given vaginally or orally.