Coitus interruptus, also known as withdrawal or the pull-out method, is a method of contraception in which a couple has sexual intercourse, but semen is ejaculated outside of and away from 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.
For couples that use withdrawal correctly at every act of intercourse, the failure rate is 4% per year. In comparison the pill has a perfect-use failure rate of 0.3%, and the IUD has a perfect-use failure rate of 0.6%. The condom has a perfect-use failure rate of 2%.
The primary cause of failure of the withdrawal method is the lack of self-control of those using it. Poor timing of the withdrawal can result in semen on the vulva, which can easily migrate into the female reproductive tract. Some medical professionals view withdrawal as an ineffective method of birth control. In contrast, a recent study in Iran found that provinces with higher rates of withdrawal use do not have higher fertility rates, and that the contribution of withdrawal use to unintended pregnancies is not markedly different from that of other commonly used methods such as the pill or condom.
It has been suggested that the pre-ejaculate ("Cowper's fluid") emitted by the penis prior to ejaculation contains spermatozoa (sperm cells), which can easily pass into the upper female genital tract in the presence of cervical mucus. However, several small studies have failed to find any viable sperm in the fluid. While no large conclusive studies have been done, it is now believed the primary cause of method (correct-use) failure is the pre-ejaculate fluid picking up sperm from a previous ejaculation. For this reason, it is recommended that users of withdrawal have the male partner urinate between ejaculations, to clear the urethra of sperm, and wash any ejaculate from objects that might come near the woman's vulva (e.g. hands and penis).
Compared to the common reversible methods of IUDs, hormonal contraceptives, and male condoms, coitus interruptus is less effective at preventing pregnancy. As a result, it is also less cost-effective than many more effective methods: although the method itself has little direct cost, users have a greater chance of incurring the risks and expenses of pregnancy and child-birth. Only models that assume all couples practice perfect use of the method find cost savings associated with the choice of withdrawal as a birth control method.
The method is largely ineffective in the prevention of STDs, like HIV, since pre-ejaculate may carry viral particles or bacteria which may infect the partner if this fluid comes in contact with mucous membranes. However, a reduction in the volume of bodily fluids exchanged during intercourse may reduce the likelihood of disease transmission compared to using no method due to the smaller number of pathogens present.
The method may be difficult for some couples to use. The interruption of intercourse may leave some couples sexually frustrated or unsatisfied.
In the United States, 56% of women of reproductive age have had a partner use withdrawal. In 2002, 2.5% were using withdrawal as their primary method of contraception.