Caps and diaphragms

Caps and diaphragms are thin, soft domes made of latex or silicone that fit inside the vagina. They stop sperm from passing through the entrance of the womb. When used with a chemical that kills sperm, they are 92-96% effective at preventing pregnancy.

Diaphragms and caps fit inside the vagina and prevent sperm passing through the cervix (the entrance of the womb). They are thin, soft domes made of latex or silicone and they come in various sizes and shapes.

To prevent pregnancy effectively, diaphragms and caps need to be used in combination with a chemical that kills sperm (spermicide). When used with spermicide, they are 92-96% effective at preventing pregnancy.


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 need to use it when you want to have sex.
  • You can put it in at a convenient time before having sex.
  • There are no serious health risks or side effects.

  • It is not as effective as some other types of contraception.
  • It provides very little protection against STIs.
  • It can take time to learn how to use it.
  • Cystitis can be a problem for some people who use a diaphragm.
  • Latex and spermicide can cause irritation in some people.