What is a diaphragm?

A diaphragm (also known as a cap) is a circular dome made of rubber, which is fitted over her cervix before sex. It acts as a barrier to stop sperm getting through to the uterus. It should be used with a spermicide cream, jelly or pessaries, which contain a chemical that destroys sperm. The diaphragm must stay in place for six hours after sex. More spermicide must be inserted again if you have sex before this time is up. Spermicides may cause irritation or an allergic reaction in some women.
A doctor or nurse will need to fit a diaphragm initially to check what size you need and teach you how to use it; but after the initial fitting you will be able to insert and remove the diaphragm each time you have sex. The diaphragm does not affect your menstrual cycle and it may protect against cancer of the cervix. Like other barrier methods, you need only use it when you are sexually active. It may protect against cancer of the cervix, however it does not protect against sexually transmitted infections (STIs) or HIV/AIDS.
If used correctly the diaphragm is 95% effective.