About diaphragms and caps

Diaphragms and caps are barrier methods of contraception. Used correctly with spermicide, they are estimated to be 92%-96% effective in preventing pregnancy. They only provide limited protection against sexually transmitted infections (STIs) so you are always advised to also use a condom.

Diaphragms look like domes and caps are smaller versions. They are soft and thin, made of latex (rubber) or silicone, and come in different shapes and sizes. To be effective in preventing pregnancy they need to be used with a spermicide (a chemical that kills sperm).

How it works

Diaphragms and caps fit inside your vagina and prevent sperm from passing through the entrance of your womb (the cervix). To be effective in preventing pregnancy, they need to be used in combination with spermicide, which is a chemical jelly that kills sperm.

How to use it

Your doctor or nurse will show you how to use a cap or diaphragm. They all come with instructions and are inserted in a similar way. For a diaphragm:

  • Fill one-third of the diaphragm with spermicide and add it to the groove between the dome and the rim. Do not put any spermicide around the rim as this will stop the diaphragm staying in place
  • Squeeze the sides of the diaphragm together and hold it between your thumb and first two fingers
  • Slide the diaphragm upwards into your vagina so that it fits neatly over your cervix. It will stay in place by suction
  • Check your cervix is covered. If it isn’t, take the diaphragm out by hooking your finger under the rim or loop (if there is one) and pulling downwards, then try again
  • You can put it in up to three hours before having sex. You must use extra spermicide if you have it in for more than three hours. After sex, you must leave the diaphragm in for at least six hours

Who can use them

Most women can use diaphragms and caps. However, they may not be suitable if you have:

  • An unusually shaped, or positioned, cervix (entrance to the womb), or if you cannot reach your cervix
  • Weakened vaginal muscles (possibly as a result of giving birth) that cannot hold a cap in place
  • Sensitivities or allergies to spermicide or latex (if you have a latex cap)
  • Ever had toxic shock syndrome (a rare, but life-threatening bacterial infection)
  • Repeated urinary tract infections like a water infection or cystitis
  • A vaginal infection at the moment. If you do, you must wait until the infection clears
  • A high risk of getting an STI – for example, if you have multiple sexual partners
  • If you are unwilling to touch your vagina

If you lose or gain more than 3kg (7lbs) in weight, or have a baby, miscarriage or abortion, you may need to be fitted with a new sized diaphragm.


There are many advantages to using a cap or diaphragm:

  • You only need to use the cap when you want to have sex
  • You can put it in up to three hours before having sex
  • No serious associated health risks or side effects


It’s also worth bearing in mind that caps and diaphragms:

  • Are not as effective as other types of contraception
  • Only provide limited protection against STIs (using condoms as well as a diaphragm or cap will help to protect against STIs)
  • Can take time to learn how to use
  • Can interrupt sex (unless inserted in advance)
  • Can cause cystitis (a bladder infection) for some women
  • Can cause a reaction in some people who are sensitive or allergic to latex and spermicide

Where to get it

Most types of contraception are free in the UK, and are available to all women and men through the NHS. Places where you can get contraception include:

  • Most GP surgeries – talk to your GP or practice nurse
  • Sexual health clinics like those run by Virgin Care, which offer both contraceptive and STI services. If you’d like to, you can book an appointment now
  • Community contraception clinics
  • Some genitourinary medicine (GUM) clinics

We do not offer the facility to book diaphragms/caps online. Please contact your local service on 0300 330 1122 for Northern Lincolnshire and Teesside or 0300 303 8565 for Oldham Bury and Rochdale so that they can assist you with this. Please note, we do not fit diaphragms/caps during walk in clinics.

Need contraception?

Useful links

  • The Family Planning Association have lots of excellent information on diaphragms and caps
  • NHS Choices provides information on all the different contraceptive methods including diaphragms and caps
  • Brook has lots of information and advice on contraception written for people under 25, including diaphragms and caps
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