What is it?

A contraceptive diaphragm or cap is a circular dome made of thin, soft silicone that's inserted into the vagina before sex.

It covers the cervix so sperm can't get into the womb (uterus) to fertilise an egg. When used correctly with spermicide, a diaphragm or cap is 92-96% effective at preventing pregnancy. This means that between four and eight women out of every 100 who use a diaphragm/cap as contraception will become pregnant within a year.

To compare contraception methods and what will work best for you, use the Contraception Choices Tool

Most people can use diaphragms and caps.

However, they might not be suitable if you:

  • Cannot reach your cervix or have and unusually shaped or positioned cervix.

  • Are not comfortable touching your genital area.

  • Have weak vaginal muscles.

  • Have an allergy to latex or the chemicals in spermicide.

  • Have ever had toxic shock syndrome.

  • Have repeated urinary tract infections.

  • Currently have a vaginal infection.

  • Have high risk of contracting an STI.

  • You only use it when you need it

  • No serious side-effects or health risks

  • 92-96% effective at preventing pregnancy 

  • Need to be trained by a health care professional before using the method

  • Is not as reliable for STI/s

  • It is not as effective as other methods of contraception 

  • cystitis (bladder infection) can be a problem for some women who use a diaphragm or cap

  • latex and spermicide can cause irritation in some women and their sexual partner

Diaphragms and caps are free through the NHS and can be found at: 

  • Our sexual clinic health clinics

  • Most GP surgeries