[Mifepristone (RU 486)]

The antiprogestin RU 486 converts the early pregnant uterus by increasing the sensitivity of the myometrium to prostaglandin (PG). These effects of antiprogestin have resulted in the development of nonsurgical procedures to abort embryos based on a combination of RU 486 and different PG-analogues administered vaginally or intramuscularly. RU 486 also has a softening effect on the cervix which may be used as pretreatment in second and third trimester abortions. The effects, mode of action, dangers, and the many other postulated clinical implications (like breast cancer, meningioma, ectopic pregnancy, fetal death in utero, induction of labour, initiation and promotion of lactation, endometrial or ovarian cancers, leukemia, Cushing's syndrome, uterine adenomyosis, acute uremia, leiomyosarcoma, hypertension, etc.) are discussed.