Diaphragms and caps are forms of contraception that prevent sperm from meeting and fertilizing an egg. They fit inside the vagina and cover the cervix (entrance to the womb). They can be made of rubber (latex) or plastic (polyurethane) and come in different shapes and sizes.
Vaginal diaphragms are circular domes with flexible rims. Caps are smaller than diaphragms. To be effective they need to be used with spermicide, which is a special cream that kills sperm.
Their effectiveness depends on how well they're used. When used according to the instructions, the effectiveness is usually greater than 90%.
Every time you have sexual intercourse, spermicide needs to be applied to the diaphragms or cap, and then inserted into the vagina to cover the cervix. They need to be left in the vagina for at least 6 hours after sex, but can be left in longer if necessary.
They can be inserted any time before sex, however if it's more than 3 hours before sex, you must apply more spermicide.
Diaphragms and caps don't suit everyone. They may not be suitable if you: