A pill containing RU–486 (mifepristone) deprives a fertilized embryo of a compatible uterine environment, terminating a pregnancy within 49 days of fertilization. It was approved for use in the United States on September 28, 2000. It is taken under the supervision of a qualified physician in a clinical setting or physician’s office. Sometimes it is used as an emergency contraceptive (“morning-after pill”) after unprotected sexual intercourse even when more than 49 days have passed since the woman’s last menstrual period.