Key points

You only have to use a diaphragm or cap when you have sex, but you must leave it in for at least 6 hours after the last time you had sex. You can leave it in for longer than this, but don’t take it out before.

You need to apply more spermicide if:

  • you have sex again with the diaphragm or cap in place
    the diaphragm or cap has been in place for three hours or more before you have sex
  • Don’t take the diaphragm or cap out to reapply spermicide.

You shouldn’t use a diaphragm or cap during your period as there is a possible link with toxic shock syndrome (TSS), a rare condition that can be life threatening.
Most women are able to use a diaphragm or cap, but it may not be suitable for you if you:

  • have an unusually shaped or positioned cervix (entrance to the womb), or if you can’t reach your cervix
  • have weakened vaginal muscles (possibly as a result of giving birth) that can’t hold a diaphragm in place
  • have a sensitivity or 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 (wait until your infection clears before using a diaphragm or cap)
    aren’t comfortable touching your vagina
  • have a high risk of getting an STI – for example, if you have multiple sexual partners

Research shows spermicides that contain the chemical nonoxynol-9 don’t protect against STIs, and may even increase your risk of getting an infection.
A diaphragm or cap may be less effective if:

  • it’s damaged – for example, it’s torn or has holes
  • it’s not the right size for you
  • you use it without spermicide
  • you don’t use extra spermicide with your diaphragm or cap every time you have more sex
  • you remove it too soon (less than 6 hours after the last time you had sex)
  • you use oil-based products, such as baby lotion, bath oils, moisturiser or some vaginal medicines (for example, pessaries) with latex diaphragms – these can damage the latex

If any of these things happen or you’ve had sex without contraception, you may need to use emergency contraception.

Advantages and disadvantages

Advantages of a diaphragm or cap:

  • you only need to use a diaphragm or cap when you want to have sex
  • you can put it in at a convenient time before having sex (use extra spermicide if you have it in for more than 3 hours)
  • there are usually no serious associated health risks or side effects
  • you’re in control of your contraception

Disadvantages of a diaphragm or cap:

  • it’s not as effective as other types of contraception, and it depends on you remembering to use it and using it correctly
  • it doesn’t provide reliable protection against STIs
  • it can take time to learn how to use it
  • putting it in can interrupt sex
  • latex and spermicide can cause irritation in some women and their sexual partners