How to choose the right contraception

What it is

The diaphragm is a dome-shaped device made from latex rubber. It's inserted into the vagina, to cover the cervix, and is kept in place by a spring within its rim, as well as by the action of vaginal muscles and by resting on an internal ledge that's formed by the pubic bone. It's important that the initial fitting is performed by a trained family planning specialist. If your weight changes by more than 3kg (half a stone), it's essential that the fit of your contraceptive diaphragm is re-checked, as you may need a different size. It's also essential to use spermicides as well. The cervical cap is smaller than a diaphragm and fits directly over the cervix.

How it works

Covers the cervix to stop sperm swimming up from the vagina into the womb. Spermicide used with it kills any sperm that find their way up around the edges. The diaphragm may be inserted either way up, but maintains the correct position more readily if inserted dome upwards. Use extra spermicide each time you make love during a session. If you have sex three hours or more after you insert a latex diaphragm or cap, always use extra spermicide. You must always check for tears or holes, by holding it up to the light before use. It must be left in place for at least six hours after the last time you had sex. You can leave it in for longer, but don't leave a rubber cap or diaphragm in for more than 30 hours.

The diaphragm is an effective form of contraception, with failure rates as low as 2% per year, when used properly. Typical failure rates are higher at around 18%.

Pros

• Can be inserted independently of intercourse, without interrupting spontaneity.
  
• No loss of sensation for either partner.
  
• May protect against cervical cancer and pelvic inflammatory disease.
  
• No side-effects.

Cons

• Requires premeditation.
  
• Requires expert sizing initially.
  
• Can be messy to use.
  
• Requires women to insert fingers into the vagina, which some find distasteful.
  
• Needs fitting checks, if weight changes significantly.
  
• May increase the risk of cystitis.
  
• There's a very small risk of toxic shock syndrome.