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Diaphragms and caps

Diaphragms and caps are barrier methods of contraception. They fit inside your vagina and cover your cervix (entrance to the womb). They come in different shapes and sizes. Vaginal diaphragms are circular domes made of thin, soft latex (rubber) or silicone with a flexible rim. Cervical caps are smaller and are made of latex or silicone. To be effective, diaphragms and caps need to be used with a spermicide. Spermicides are chemicals that kill sperm.

How effective are diaphragms and caps?

How effective any contraceptive is depends on how old you are, how often you have sex and whether you follow the instructions.

If 100 sexually active women don’t use any contraception, 80 to 90 will become pregnant in a year. If used according to instructions, latex diaphragms and caps are 92-96% effective when used with spermicide. This means that between four and eight women in 100 will get pregnant in a year. The silicone cap FemCap is less effective. If they are not used according to instructions, more women will get pregnant.

How does a diaphragm or cap work?

A diaphragm or cap stops sperm reaching an egg. It covers your cervix while the spermicide kills any sperm. To be more effective in preventing a pregnancy, you must use spermicide with a diaphragm or cap.

Can anything make a diaphragm or cap less effective?

A diaphragm or cap will be less effective if:

  • you don't use it every time you have sex
  • it doesn't cover your cervix
  • you don't have the right size
  • you use it without spermicide
  • you have sex three hours or more after you put it in and you don't use extra spermicide
  • you don't use extra spermicide with you diaphragm or cap every time you have more sex
  • you remove it too soon (less than six hours after the last time you had sex)
  • you use oil-based products such as baby lotion, bath oils or some vaginal medicines (pessaries) with latex diaphragms or caps. These can damage the latex.

If any of these happen, or if you have had sex without using contraception, you can get advice about emergency contraception

What are the different types of diaphragm and cap?

There are three types of latex vaginal diaphragm: flat, coil, or arcing spring. There are two silicone diaphragms - a coil and arcing spring type. All types come in different sizes.

There are also three types of latex cap: vault, cervical and vimule. There is currently one variety of silicone cap (FemCap). Caps come in different sizes. A doctor or nurse can help you decide which is best for you after they have examined you.

What are the advantages of a diaphragm or cap?

  • You only have to use it when you have sex 
  • It has no serious health risks.
  • You are in control of your contraception
  • There is a choice of different types
  • You can put it in at any convenient time before you have sex
  • It may give you some protection against cervical cancer and some sexually transmitted infections


What are the disadvantages of a diaphragm or cap?

  • Putting it in at the time of sex can be an interruption.
  • Some people find the spermicide messy.
  • It can take time to learn how to use it.
  • Cystitis can be a problem for some women who use a diaphragm. Ask the doctor or nurse to check the size of your diaphragm if you suffer from cystitis. Changing to a slightly smaller or softer-rimmed (coil spring) diaphragm or to a cervical cap may help.
  • Some people are sensitive to the chemicals in latex or spermicide. This may cause irritation in some women and their partners.

Can anyone use a diaphragm or cap?

Most women can use a diaphragm or cap. A diaphragm or cap may not be suitable if you:

  • have vaginal muscles which can't hold a diaphragm
  • have a cervix of an unusual shape or in an awkward position or you cannot reach it
  • are sensitive to the chemicals in latex or spermicide
  • have repeated urinary infections
  • have a vaginal infection (wait until after the infection has cleared)
  • have ever had toxic shock syndrome
  • do not feel comfortable touching your vagina.

If you have a high risk of getting a sexually transmitted infection (STI), for example if you or your partner has more than one partner, it may be advisable not to use a diaphragm or cap. Research shows that spermicide (Nonoxinol 9), which needs to be used with a diaphragm or cap to prevent pregnancy, does not protect against STIs. It may even increase the risk of getting an STI such as chlamydia or HIV.

Where can I get a diaphragm or cap?

You can get a diaphragm or cap from some family planning clinics and some general practices. If you know the size and type of diaphragm or cap you use, you can buy them from a pharmacy.

How do I put a diaphragm in?

Instructions on how to use a diaphragm come with it and a doctor or nurse will show you how to put it in. The different types of diaphragm are all used in a similar way. With clean hands, put a small amount of spermicide cream or jelly on each side of the diaphragm (approximately two 2cm strips). Some women find that putting a little spermicide on some of the rim makes the diaphragm easier to put in.

Put your index finger on top of the diaphragm and squeeze it between your thumb and other fingers. Slide the diaphragm into your vagina downwards and backwards. This should ensure that the diaphragm covers your cervix.

Always check that your cervix is covered. It feels like the end of your nose. If your cervix is not covered, take the diaphragm out by hooking your finger under the rim or loop (if there is one) and pulling downwards and try again.

Some women squat while they put their diaphragm in. Others lie down or stand with one foot up on a chair. You will need to find out which position is easiest for you.

How do I put a cap in?

Instructions on how to use a cap come with it. The different types of cap are all used in a similar way.

Fill one-third of the cap with spermicide, but don’t put any spermicide around the rim as this will stop the cap from staying in place. FemCap has a groove between the dome and the rim; some spermicide should also be placed there. Squeeze the sides of the cap together and hold it between your thumb and first two fingers. The cap must fit neatly over your cervix. It stays in place by suction. Always check that your cervix is covered. Depending on the type of cap, you may need to add extra spermicide after it has been put in.

How do I take my diaphragm or cap out?

You must leave all types of diaphragm and cap in place for at least six hours after the last time you had sex. You can leave it for longer, but don’t leave a diaphragm or cap in for more than the recommended time. For latex types this is 30 hours, including the minimum six hours and for FemCap, 48 hours including the minimum six. Take it out by gently hooking your finger under the rim, loop or strap and pulling downwards.

How do I look after my diaphragm or cap?

When you take your diaphragm or cap out, wash it in warm water with a mild unperfumed toilet or baby soap. Then rinse it thoroughly. Dry it carefully and keep it in its container in a cool, dry place. Never boil your diaphragm or cap, never use disinfectant or detergent to clean it or use talcum powder with it. Do not use any oil-based product with latex types as it will damage them.

Before use, check your diaphragm or cap regularly for tears or holes by holding it up to the light and having a good look at it. Be careful with your nails and jewellery. If your diaphragm goes out of shape, squeeze it gently back into its circular shape. Your diaphragm or cap may become discoloured. But don’t worry, this will not make it less effective.

Can I use my diaphragm or cap during my period?

Ideally diaphragms and caps should not be used during your period because of a possible risk of toxic shock syndrome (TSS). Never leave them in for longer than the recommended time.

Can I have a bath when I've got my diaphragm or cap in?

Put your diaphragm or cap in after a bath rather than before. This is because water may move its position or wash away the spermicide. Have a shower rather than a bath during the six hours that you need to keep your diaphragm or cap in after you have had sex. The effect of swimming or water sports has not been studied, but it is likely to be small.

What is a practice diaphragm or cap?

A doctor or nurse will sometimes fit you with a practice diaphragm or cap that should be the right size for you. Practice diaphragms and caps give you time and privacy to find out if the method is suitable for you and to learn how to use it properly. While you are learning to use it, don’t rely on it to stop you getting pregnant. You will need to use another method of contraception, such as condoms, if you have sex.

During this time try putting the diaphragm or cap in and check that it covers your cervix. You can have sex with the diaphragm or cap in place and leave it in for a few hours to find out if it is comfortable for you and your partner. It is also a good idea to use the spermicide jelly or cream to see how this feels.

When you go back to get it checked, wear the diaphragm or cap so the doctor or nurse can check that you have put it in properly and that it is still the right size. Ask them any questions you have about using the diaphragm or cap.

How often do I need to see a doctor or nurse?

Once you have a diaphragm or cap that you are happy with, you only need to see a doctor or nurse to replace it, usually once a year, or if you have any questions or concerns. You may need a different size diaphragm or cap if you put on or lose more than 3kg (7 pounds) in weight.

Can I use my diaphragm or cap again after I've been pregnant?

You will probably need a different size diaphragm or cap after you have a baby or after you have a miscarriage or an abortion.

How do I find out about contraception services?

Contraception is free for women and men of all ages through the National Health Service.

  • You can find out about all clinics from sexual health direct, run by fpa on 0845 310 1334 or visit the website
  • You can get lists of GPs from libraries, primary care trusts or health boards and some advice centres and helplines
  • You can get details of your nearest family planning or sexual health clinic from: local directories, health centre, hospital, midwife or health visitor, advice centre, NHS Direct on 0845 46 47 (NHS 24 in Scotland 0845 4 24 24 24), primary care trust or health board
  • Young people can also phone Brook on 0800 0185 023 or Sexwise on 0800 28 29 30 for details of the nearest young people’s clinic.

Emergency contraception

If you have had sex without using contraception or think your method might have failed there are two emergency methods you can use.

  • Emergency hormonal pills - must be taken up to three days (72 hours) after sex. They are more effective, the earlier they are taken after sex
  • An IUD - must be fitted up to five days after sex, or up to five days after the earliest time you could have released an egg (ovulation).

Ask your doctor or nurse about getting emergency pills in advance, just in case you need them.

Sexually transmitted infections

Most methods of contraception do not protect you from sexually transmitted infections.

Male and female condoms, when used correctly and consistently, can help protect against sexually transmitted infections. Diaphragms and caps may also protect against some sexually transmitted infections. If you can, avoid using condoms containing Nonoxinol 9 (spermicidally lubricated), as this does not protect against HIV and may even increase the risk of infection. How fpa can help you sexual health direct is a nationwide service run by fpa. It provides:

  • confidential information and advice on contraception, sexually transmitted infections, planning a pregnancy, pregnancy choices and sexual wellbeing
  • details of family planning clinics, sexual health clinics and other sexual health services
  • a wide range of leaflets on individual methods of contraception, common sexually transmitted infections, abortion and planning a pregnancy.


Northern Ireland
Phone 028 90 325 488
Derry 028 71 260 016
9am to 5pm Monday to Thursday, 9am to 4.30pm Friday

Phone 0141 576 5088
9am to 5pm Monday to Thursday, 9am to 4.30pm Friday

or visit fpa's website

A final word

This leaflet can only give you basic information about the the diaphragm/cap. The information is based on the evidence and medical opinion available at the time this information was published. Different people may give you different advice on certain points. All methods of contraception come with a Patient Information Leaflet which provides detailed information about the method.

Remember - contact your doctor, practice nurse or a family planning clinic if you are worried or unsure about anything.

Registered charity number 250187 - Supported by the Department of Health - © fpa

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