Emergency contraception: The prevention of pregnancy after unprotected vaginal intercourse. Emergency contraception may use drugs related to the female hormones estrogen and progesterone. These "morning-after pill" are similar to birth control pills but generally contain higher hormone doses. Another form of emergency contraception uses an intrauterine device (IUD) inserted by a physician within 5 days after intercourse.
Emergency contraception is also known as emergency birth control; emergency postcoital contraception; and postcoital contraception.