Yet clinical trials on most of these uses in the U.S. have come to a standstill because of anti-abortion politics. In the absence of clinical trials, several dozen people with Cushing's Syndrome, meningioma, and breast cancer are currently being treated with mifepristone under compassionate use protocols.
Mifepristone blocks the action of progesterone, which is necessary to sustain a pregnancy.
Mifepristone, taken in pill form in conjunction with a prostaglandin, has been used by over 200,000 women worldwide and has been found to be safe and effective as a method of early abortion during the first nine weeks of pregnancy. A woman can take mifepristone as soon as she knows that she is pregnant. The administration of mifepristone is non-invasive, has less risk of infection, and does not require anesthesia. Many women prefer mifepristone because the procedure is more private and allows them greater psychological control over the termination of pregnancy. Preliminary studies show RU 486 potentially can act as both a male and female contraceptive.