Diaphragm and cap

What are they?

Diaphragms and caps are barrier methods of contraception, which means they prevent the sperm meeting an egg.

They fit inside the vagina and cover the cervix (entrance to the womb). They're made of latex (rubber) or polyurethane (plastic). They come in different shapes and sizes.

Vaginal diaphragms are circular domes with flexible rims. Caps are smaller than diaphragms. To be effective they need to be used with spermicide - a special cream or pessary that kills sperm.

Myths about diaphragms and caps:

• Only women who've had children can use this method. Not true - diaphragms and caps come in different sizes and types to suit all women.
• You can use them without spermicide. Not true - to be effective they need to be used with a spermicide.

How reliable are they?

Their effectiveness depends on how carefully they're used. They are 92-96 per cent effective when used according to instructions. This means that using either method, between four and eight women in 100 will get pregnant in a year. The silicone cap - Femcap - has a higher failure rate.

How do I use a diaphragm or cap?

Firstly you need to see your doctor or family planning nurse to be examined, assessed for size and shown how to use one. Diaphragms and caps need to be used each time you have sex. Spermicide is applied to the diaphragm or cap, which is then inserted into the vagina to cover the cervix. They can be inserted any time before sex, but if it's more than three hours before sex you must use more spermicide.

The cap or diaphragm needs to be left in place for at least six hours after the last time you had sex. It can be left in longer if necessary.

Advantages and disadvantages

The advantages of diaphragms and caps include:

• You only have to use them when you have sex
• There are no serious health risks
• There's a choice of different types
• They can be put in at any convenient time before sex
• They may give some protection against cervical cancer

The disadvantages include:

• Putting them in at the time of sex can be an interruption
• Some people find the spermicide messy
• Some diaphragm users find they get cystitis (changing to a smaller diaphragm or cap can help)
• Some people are sensitive to the chemicals in latex diaphragms or caps or to the spermicide
• Oil-based lubricants such as body oils or lotions should not be used with latex diaphragms or caps

Other things to consider include:

• You can buy diaphragms and caps if you know your size
• You may need a different size if you gain or lose more than 3kg (7lb) in weight, have a baby, miscarriage or abortion

Who can use a diaphragm or cap?

Diaphragms and caps don't suit everyone. They may not be suitable if you:

• Have vaginal muscles that can't hold a diaphragm
• Have a cervix of an unusual shape or in an awkward position or you can't reach it
• Have had repeated urinary infections
• Have had toxic shock syndrome in the past
• Don't feel comfortable touching your genital area

Where can I get a diaphragm or cap?

They're free on the NHS from contraception clinics, sexual health clinics and from your GP (if your surgery offers contraceptive services). You can buy them from a pharmacy, if you know your size.

Advice and support

Call the FPA helpline on 0845 122 8690.