Many readers have asked us: Is it possible to get pregnant from sperm on clothes or fingers? What about from oral or anal sex or from any other ways of sexual expression? To answer these important questions, we should review some of the basics of pregnancy.
For a pregnancy to occur, a single sperm must penetrate the surface of a woman's egg in the fallopian tube. The fertilized egg then travels to the uterus and implants on the uterine surface. This usually occurs during vaginal intercourse when the erect penis is inserted into the vagina and ejaculation occurs within the vagina.
The millions of sperm released at this time move through the uterus and some may find the egg. Ultimately, one sperm may fertilize the egg. Teenagers who engage in vaginal intercourse without any form of contraception have up to a 90% chance of becoming pregnant.
Did You Know?
Of sexually active Canadian teens aged 15-17, 22% reported having sex without a condom If the penis is removed before ejaculation (called the "withdrawal" method of contraception), there is still a 20% failure rate per encounter, which means that one pregnancy can occur for every 5 times a person engages in "withdrawal" intercourse. If the penis is not in the vagina, but close to it, some of the sperm can still reach the uterus and subsequently the fallopian tubes and therefore can lead to pregnancy.
What about anal sex? Technically, if the man's ejaculating penis is in a woman's anus, the sperm cannot reach the fallopian tubes because there is no connection between these areas of the body. However, if there are any sperm on the skin surrounding the anus, the sperm may be able to migrate to the vagina. Pregnancy can therefore occur, but would be rare.
Did You Know?
Sperm are produced in the testes, where it takes approximately 10 weeks for a single sperm to reach maturity Nevertheless, sexually transmitted infections (aka STIs) are often more easily acquired with anal intercourse and condoms should always be used. A similar rationale applies to oral sex; pregnancy can occur only if the sperm gets near or in the vagina, but STIs, such as gonorrhoea and herpes, are transmittable.
Also, teens should not feel pressured to participate in any type of sex solely to prevent pregnancy (there are many other contraceptive measures — see The Clinic's article on Contraception for more information); it should be a mutual choice, comfortable for both partners.
Did You Know?
The term sexually transmitted infection (STI) is now commonly used in place of sexually transmitted disease (STD) in order to include infections that may be asymptomatic. Sometimes sperm can get onto fingers, articles of clothing and sex toys. Sperm-covered anything in the vicinity of the vagina can lead to pregnancy and STIs. And to complicate matters, sperm have been known to survive up to 24 hrs after ejaculation, so the potential for pregnancy can exist long after the sexual encounter. Also, sex toys should never be shared; the risk for STIs is high.
To learn more about preventing pregnancy, see previous articles in The Clinic as well as the links below. Stay-tuned for more details on sexually transmitted infections.
Dr. Barra obtained her medical degree at the University of Western Ontario and is currently completing her internal medicine residency in London, Ontario. She was born and raised in Toronto and loves gelato.