Fertility control in women: results with RU 486 by the end of 1985.

RU 486 is the first antiprogesterone to be used clinically. It inhibits the action of the hormone at the receptor level in target tissues. Its action is particularly significant in the endometrium where it prevents the initiation and progression of pregnancy in the first weeks (contragestive effects). The data indicate that the compound can be used for: voluntary interruption of pregnancy between 6 and 10 weeks, induction of menstruation during the fifth week of amenorrhea, and post-coital contraception. Current trials include its use as a once-a-month menses inducer. It can also be utilized for therapeutic interruption at a late stage of pregnancy, and tried as adjuvant treatment in some case of breast cases. The data on RU 486 have been obtained through studies in physio-pharmacological endocrinology and biochemistry. The development of this antihormone represents a concerted research effort between biology and medicine.