Diaphragms and caps

Diaphragms are dome-shaped rubber devices that fit into the vagina and over the cervix (the neck of the womb). Cervical caps are smaller and need to be put directly onto the cervix.

Diaphragms and caps must be fitted by a trained doctor or nurse on the first occasion and thereafter you can fit them yourself. You can have one fitted at most sexual health clinics.

Both the diaphragm and the cap work by stopping sperm from entering the womb by covering the cervix. You need to use spermicide (a gel which kills sperm)​ as well.

You simply put the spermicide on the diaphragm and then place it inside the vagina to cover the cervix each time you have sex. You can put the diaphragm in a short time before you have sex but if you put it in more than three hours before sex you will need to use extra spermicide. You must leave the diaphragm in for at least six hours after having sex.

If they are used correctly, diaphragms and caps are 92 – 96% effective at preventing pregnancy. This is less effective than other methods of contraception.