Coitus Interruptus

The main risk of coitus interruptus is that it's not a very effective method of birth control. First, it relies heavily on the genetic male partner’s ability to recognize the timing of ejaculation and withdraw in time, which may be difficult to do during intercourse. Withdrawing prior to ejaculation can interrupt sexual pleasure abruptly and end up reducing satisfaction for both partners. Additionally, even when performed correctly, there may be small amounts of sperm in the pre-ejaculate fluid that could result in pregnancy before withdrawing.  

Another important risk of coitus interruptus is that it doesn’t prevent sexually transmitted infections (STIs), such as chlamydia, gonorrhea, or trichomoniasis. Among all contraceptive methods, abstinence or condoms are the only methods that protect against STIs. Condoms are the method of choice for individuals who have a new sexual partner or have multiple sexual partners.   

Even with its risks, some individuals may rely on the withdrawal method because it can be used without any preparation and it is completely free, as it does not require any devices, medications, or prior medical appointments. Unlike hormonal methods (e.g., birth control pills, patches, vaginal rings), coitus interruptus doesn’t interfere with the menstrual cycle, so couples trying to conceive can easily decide to try for pregnancy. 

Coitus interruptus has a low efficacy compared to other contraception methods. With contraceptives, effectiveness is measured by the number of pregnancies that occur in 100 females over a year. The lower the number, the better the method of contraception is at preventing pregnancy.   

The typical failure rate of coitus interruptus is around 22%, meaning about 22 in 100 individuals, or 1 in about 5 individuals using this method for a year may become pregnant. For reference, the most effective contraceptive methods have an index of less than 1 pregnancy in 100 individuals in a year. These methods include long-acting reversible contraception methods, like intrauterine devices (IUDs) and contraceptive implants, and irreversible methods, like a vasectomy and bilateral tubal ligation. Other common methods of birth control, such as contraceptive pills, patches, vaginal rings, and hormonal injections are a little less effective, with 4 to 7 pregnancies in 100 females in a year.