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Diaphragms and caps

Diaphragms are a method of contraception and are dome-shaped devices (of either latex or silicone) that fit into the vagina and over the cervix. Cervical caps are also a method of contraception, but are smaller and need to be put directly onto the cervix (these are made of silicone).

Diaphragms and caps must be fitted by a trained doctor or nurse on the first occasion. This method of contraception may not be available at your local clinic, so it is best to contact the clinic to discuss first, and then you can be signposted to another local service if they are not able to provide it. 

Here are some key facts:

  • Diaphragms and caps are between 92-96% effective when used correctly
  • To be effective, diaphragms and caps should be used with a spermicide (chemicals that kill sperm)
  • Diaphragms are made of thin, soft latex or silicone and have a flexible rim. Cervical caps are smaller and are made silicone (they used to be made of latex but newer caps are now made of silicone)
  • They protect against pregnancy but not sexually transmitted infections (STIs). To protect against STIs you will also need to use a additional method of contraception such as condoms
  • You don’t have to think about it every day, you only have to use diaphragms and caps when you have sex, you can put them in beforehand but you must leave them in for at least six hours afterwards
  • It can take a while to get used to putting them in and using the spermicide

This page should tell you everything you need to know about diaphragms and caps but if you have more questions, you can get in touch with Ask Brook via webchat or text on 07717 989 023 (standard SMS  rates). Contacting Ask Brook is confidential. That means we won’t tell anyone you’ve contacted us unless we think you are in really serious danger.

How do diaphragms and caps work?

Pregnancy happens when sperm reaches an egg and fertilises it. Both the diaphragm and the cap are barrier methods which work by stopping sperm from entering the womb by covering the cervix. It is recommended that you also use a spermicide with the diaphragm/cap. The spermicide is a gel which contains chemicals that kill the sperm.

Although diaphragms and caps protect against pregnancy, they don’t protect against sexually transmitted infections (STIs). To be protected against STIs, condoms should be used in addition to diaphragms and caps.

You only need to use diaphragms and caps when you have sex, and you must leave then in for at least six hours afterwards.

If they are used correctly, diaphragms and caps are 92-96% effective when used with spermicide. This means that between four and eight women out of every 100 who use a diaphragm or cap as contraception will become pregnant within a year. This is less effective than other methods of contraception – if you are thinking about using a diaphragm or cap as your only method of protection against pregnancy you may wish to speak with a doctor or nurse about the other methods that are available.

How do I get diaphragms or caps?

This method of contraception may not be available at your local clinic. It is best to contact your local clinic to discuss first and then you can be signposted to a local service which is able to accommodate your needs.

Diaphragms and caps are available free of charge from contraception and sexual health clinics, such as:

Diaphragms and caps may be less readily available at Brook services. It is best to contact us in advance to discuss first and if needs be, we can signpost you to a local service which is able to accommodate your needs.

You can find your nearest Brook service by clicking here or if there is no Brook service near you, search sexual health services on NHS Choices here or SXT.

When you go to get the diaphragm or cap, you will be asked a few questions about your medical and family history. This is to work out if the diaphragm or cap is most suitable for you, or if another form of contraception would be more suitable. A doctor or nurse will examine you and recommend the size or shape to suit you. They will also show you how to insert the diaphragm or cap, how to use spermicide and also how to take the diaphragm or cap out.

When you first start using diaphragms or caps you may be fitted with a temporary ‘practice’ diaphragm or cap by your doctor or nurse so that you can learn how to use it and see how it feels. You will not be protected from pregnancy during this time and will also need to use additional contraception such as condoms. When you go back to get it checked you should wear the diaphragm or cap so that the doctor or nurse can check it is the right size.

Once you have had the diaphragm or cap fitted, you will only need to go back to the doctor or nurse to replace it (most people can use the same one for a year) or if you have any questions or concerns. You may also need to get a different size diaphragm or cap fitted if you gain or lose more than 3kg (7lb) in weight, or if you have a baby, miscarriage or abortion.

Diaphragms and caps are suitable for most women. But some women can be sensitive to the silicone, or sensitive or allergic to the spermicides. There may be other reasons why the diaphragm or cap is not the most appropriate method of contraception for you. The doctor or nurse will discuss this with you to make sure that this is the most appropriate method of contraception for you.

Contraception and sexual health services such as Brook are free and confidential, including for people under the age of 16. Health professionals work to strict guidelines and won’t tell anyone else about your visit unless they believe you're at serious risk of immediate harm. Find out more about Brook’s confidentiality policy here.

How do you use diaphragms and caps?

Diaphragms and caps come with instructions on how to use them, and a doctor or nurse will also show you show to use them. You put the spermicide on the diaphragm or cap and then place them inside the vagina to cover the cervix each time you have sex. You can put the diaphragm in a little time before you have sex but if you put it in more than three hours before you will need to use extra spermicide. You should avoid using diaphragms or caps during your period because of the possible risk of toxic shock syndrome.

Putting diaphragms in:

Different types of diaphragm are used in a similar way, and you should follow the instructions that come with the diaphragm and how the doctor or nurse has instructed you to use it. Some general instructions are:

  • Find a position that’s comfortable for you, and with clean hands, put a small amount of spermicide on the upper surface of the diaphragm (some women find that putting a little spermicide on 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 upwards and backwards
  • Always check that your cervix is covered (it feels like a lump bit 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
  • You can insert a diaphragm up to three hours before you have sex, after this time you will need to take it out and put more spermicide on it

Putting caps in:

Different types of caps are used in a similar way, and you should follow the instructions that come with the cap and how the doctor or nurse has instructed you to use it. Some general instructions are:

  • 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. The silicone cap also has a groove between the dome and the rim and some spermicide should be placed there too
  • Find a position that’s comfortable for you and squeeze the sides of the cap together, holding it between your thumb and first two fingers. The cap must fit neatly over your cervix and 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
  • You can insert a cap up to three hours before you have sex – after this time, you will need to take it out and put some more spermicide on it

How to take out diaphragms or caps:

You must leave all types of diaphragm or cap in place for at least six hours after the last time you had sex. You can leave it for longer, but not for more than the recommended maximum time (30 hours for latex types, and 48 hours for the silicone cap, including the minimum six hours). However you should check the leaflet that came with your diaphragm or cap for recommended duration times.

Take the diaphragm or cap out by gently hooking your finger under the rim, loop or strap and then pulling downwards.

How to look after diaphragms and caps

You should follow the instructions in the packet on how to look after your diaphragm or cap, some general points are below:

  • When you have taken your diaphragm or cap out, wash it in warm water using mild, unperfumed soap, rinse thoroughly and dry it carefully, storing it in its container in a cool, dry place.
  • Never boil diaphragms or caps, never use disinfectant, detergent or talcum powder. 
  • Do not use any oil-based product with latex types as it will damage the latex.
  • Before using your diaphragm or cap, check it regularly for tears or holes, and be careful with fingernails or jewellery
  • Your diaphragm or cap may become discoloured, but this won’t make it less effective

Advantages of diaphragms and caps

  • They can be put in before sex so they don't disturb the moment (you will need to add extra spermicide if you have sex more than three hours after putting it in)
  • They are not affected by any medicines that you take in tablet/oral form
  • They don't disturb your menstrual cycle 

Disadvantages of diaphragms and caps

Any medication can have some side effects and a very small number of women may develop complications, but discussing you and your family’s medical history with the doctor or nurse will help reduce the risk of negative side effects.

For most women the benefits will outweigh the possible risks. Thing to watch out for include:

  • The first fitting must be done by a trained doctor or nurse to make sure it's the right size
  • They don't protect you against STIs
  • They can take a little getting used to before you're confident using them 
  • Some people may be sensitive to latex or the chemical used in spermicide
  • They aren’t as effective as other methods of contraception
  • Some women can develop the bladder infection cystitis when using diaphragms or caps – check with your doctor or nurse
  • It is recommended that you do not use the diaphragm/cap during your period, so you will need to use an alternative method of contraception at this time

What can make diaphragms and caps less effective?

  • You must leave it in for at least six hours after having sex. You'll need to use more spermicide if you have sex again, or if you have sex more than three hours after putting it in.
  • If it is damaged
  • If you use it without spermicide
  • If it isn’t the right size or doesn’t cover your cervix
  • Using oil based products such as baby lotion, bath oils or moisturiser can damage the latex
  • Some vaginal medicines/pessaries can also damage the latex

Using diaphragms and caps after having a baby

You may need a different size diaphragm or cap after you have had a baby. It is also recommended to wait at least six weeks after having a baby before using a diaphragm or cap. You can find out about other methods of contraception here.

Using diaphragms and caps after an abortion or miscarriage

You can use a diaphragm or cap after a miscarriage or abortion, however you may need a different size so will need to check with a doctor or nurse.

Page last reviewed: July 2015
Next review due: July 2016