A diaphragm is a shallow, bendable cup made of thin, flexible silicone that sits over the cervix, the part of the uterus that opens into the vagina. It is a form of birth control that works as a barrier that covers the cervix, stopping sperm from joining an egg. To be effective in preventing pregnancy, diaphragms need to be used with spermicide, a chemical that kills sperm. Adding spermicide to the diaphragm before inserting it into the vagina makes it much more effective. The diaphragm is placed high into the vagina so it covers the cervix. It must be left in place for at least 6 hours after the last time you had sex.

A diaphragm is a type of contraception that fits inside the vagina and prevents sperm from passing through the cervix. It is a barrier method of contraception that is made of soft, thin domes made of silicone, and comes in different shapes and sizes. It is a good option for a young woman who can take responsibility for protection before having sex. However, it may not be suitable for everyone, such as those with an unusually shaped or positioned cervix, vaginal muscles that cannot hold a diaphragm in place, or a sensitivity or allergy to latex or the chemicals in spermicide.

Possible side effects of using a diaphragm include irritation of the vagina and surrounding skin or an allergic reaction from the spermicide, strong odors or vaginal discharge if the diaphragm is left in too long, an allergic reaction to the material in the diaphragm, a higher risk for urinary tract infections (UTIs), and toxic shock syndrome if the diaphragm is left in too long. A diaphragm provides less protection against sexually transmitted infections (STIs) than a condom, and spermicides can irritate the skin in the vagina and make it easier for an STI to be passed from your partner.