Diaphragms and caps are barrier methods of contraception. They fit inside your vagina and prevent sperm from passing through the entrance of your womb (the cervix).
Diaphragms are soft, thin domes made of latex (rubber) or silicone. Caps are smaller and are also made of latex or silicone. They come in different shapes and sizes.
To be effective in preventing pregnancy, they need to be used in combination with spermicide, which is a chemical that kills sperm.
You only have to use a diaphragm or cap when you have sex, but you must leave it in for at least six hours after the last time you had sex. You can leave it in for longer than this, but do not take it out before.
Read more about how to use diaphragms and caps.
How effective are diaphragms and caps?
If used correctly and in combination with spermicide, diaphragms and caps are estimated to be 92%-96% effective in preventing pregnancy. This means that if 100 women use a diaphragm or cap, between four and eight of them will become pregnant in one year.
There are other more effective contraceptives available, such as the oral contraceptive pill. Some women prefer to use diaphragms or caps because they do not like taking the pill. Others can’t take the pill for health reasons.
Diaphragms and caps only provide limited protection against sexually transmitted infections (STIs). If you’re at a high risk of getting an STI – for example, you or your partner has more than one sexual partner – you may be advised to use another form of contraception.
Read more about things to consider before using diaphragms and caps.
Where can I get a diaphragm or cap?
You can get a diaphragm or cap from:
- contraception clinics
- young people’s services
- your GP
- sexual health clinics (GUM clinics)
Go to the NHS Choices service directory to check for sexual health services and GPs in your area.
- Cervix
- The cervix is at the lower end of the womb. It connects the womb with the vagina.