Cervical cap

The cervical cap is a form of barrier contraception. A cervical cap fits over the cervix and blocks sperm from entering the uterus through the external orifice of the uterus, called the os. The term cervical cap has been used to refer to a number of barrier contraceptives, including the Prentif, Dumas, Vimule, and Oves devices. In the United States, Prentif was the only brand available for several decades (Prentif was withdrawn from the U.S. market in 2005). During this time, it was common to use the term cervical cap to refer exclusively to the Prentif brand. The Lea's Shield was a cervical barrier device which was discontinued as of 2008. Some sources use cervical cap to refer to the FemCap and Lea's Shield. Other sources include FemCap in the term cervical cap, but classified the Lea's Shield as a distinct device. In the 1920s, cervical caps (and also diaphragms) were often just called pessaries. Cervical caps or conception caps have also been designed as a form of assisted reproductive technology, used to help people experiencing infertility. The effectiveness of cervical caps, as with most other forms of contraception, can be assessed two ways: method effectiveness and actual effectiveness. The method effectiveness is the proportion of couples correctly and consistently using the method who do not become pregnant. Actual effectiveness is the proportion of couples who intended that method as their sole form of birth control and do not become pregnant; it includes couples who sometimes use the method incorrectly, or sometimes not at all. Rates are generally presented for the first year of use. Most commonly the Pearl Index is used to calculate effectiveness rates, but some studies use decrement tables. Contraceptive Technology reports that the method failure rate of the Prentif cervical cap with spermicide is 9% per year for nulliparous women (women who have never given birth), and 26% per year for parous women (who have given birth). The actual pregnancy rates among Prentif users vary depending on the population being studied, with yearly rates of 11% to 32% being reported.