: a drug C29H35NO2 taken orally to induce abortion especially early in pregnancy by blocking the body's use of progesterone—called also mifepristone
Common name for mifepristone, a drug used in the first several weeks of pregnancy for inducing abortion. RU-486 blocks the receptors for progesterone, a hormone necessary for the maintenance of pregnancy. The drug causes the breakdown of the uterine lining, which, along with the embryo, is shed through the vagina. It has been available in France for the termination of early pregnancy since 1988 and was approved for use in the U.S. in 2000. The name RU-486 is derived from the manufacturer Roussel-Uclaf and a serial number.