A condom is a sheath-shaped barrier device used during sexual intercourse to reduce the probability of pregnancy or a sexually transmitted infection STI. The external condom is rolled onto an erect penis before intercourse and works by forming a physical barrier which limits skin-to-skin contact, exposure to fluids , and blocks semen from entering the body of a sexual partner.
Condoms as a method of preventing STIs have been used since at least The effectiveness of condoms, as of most forms of contraception , can be assessed two ways.
Perfect use or method effectiveness rates only include people who use condoms properly and consistently. Actual use , or typical use effectiveness rates are of all condom users, including those who use condoms incorrectly or do not use condoms at every act of intercourse.
Rates are generally presented for the first year of use. Condoms are widely recommended for the prevention of sexually transmitted infections STIs. They have been shown to be effective in reducing infection rates in both men and women. While not perfect, the condom is effective at reducing the transmission of organisms that cause AIDS , genital herpes , cervical cancer , genital warts , syphilis , chlamydia , gonorrhea , and other diseases. The NIH review concluded that condom use significantly reduces the risk of gonorrhea for men.
Although a condom is effective in limiting exposure, some disease transmission may occur even with a condom. Infectious areas of the genitals, especially when symptoms are present, may not be covered by a condom, and as a result, some diseases like HPV and herpes may be transmitted by direct contact.
