The diaphragm is sometimes also known as the cap.

It is:

  • 92-96% effective when you use the method correctly every time
  • 71-88% when you don’t always use the method correctly

What is it?

The diaphragm or cap is a soft silicone device which is put into the vagina to cover the cervix (neck of the womb). A doctor will examine you and advise on the correct size. You can use spermicide to cover the diaphragm. This will help it work better.

How does it work?

The diaphragm covers the woman’s cervix and this stops the sperm from reaching the egg. Spermicide is a gel that kills sperm and is most effective in protecting against pregnancy when used with another contraceptive method like a diaphragm.

It is important that you talk to a doctor who will assess what contraceptive option is best for you.


  • You can put the diaphragm in place any time before you have sex.
  • You can re-use the diaphragm after careful washing with water.
  • It is useful if you want to avoid taking hormones.


  • You need to have a check-up at least once a year to make sure it still fits.
  • You may need a different size diaphragm if you put on or lose more than three kilos (seven pounds) in weight.
  • You must leave the diaphragm in place for at least 6 hours after sex, but must not leave it in for more than 24 hours.
  • It does not protect you against sexually transmitted infections (STIs).
  • If you have sex again, you need to use extra spermicide.