Coitus interruptus, also known as withrawal or the pull out method, is a method of contraception in which, during sexual intercourse, the penis is removed from the vagina prior to ejaculation, primarily to avoid introducing semen into the vagina. Coitus interruptus may also more generally refer to any extraction of the penis prior to ejaculation during intercourse. This method has been widely used for at least 2,000 years and was used by an estimated 38 million couples worldwide in 1991.