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Diaphragms and caps

Diaphragms are dome-shaped rubber devices that fit into the vagina and over the cervix. Cervical caps are smaller and need to be put directly onto the cervix.

Diaphragms and caps must be fitted by a trained doctor or nurse on the first occasion. You can have one fitted at most contraception and sexual health clinics.

Spend a bit of time looking here and finding out more about diaphragms and caps. If you can’t find what you’re looking for here, or if you have more questions, you can get in touch with Ask Brook. 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?

Both the diaphragm and the cap work by stopping sperm from entering the womb by covering the cervix. You need to use spermicide as well (a gel which kills sperm) too.

How do you use a diaphragms and caps with spermicide?

You simply put the spermicide on the diaphragm 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.

What's good about diaphragms and caps?

  • Can be put in before sex so they don't disturb the moment
  • Not affected by any medicines
  • You can't feel them during sex
  • They don't disturb your menstrual cycle. 

What do I need to watch out for with diaphragms and caps?

  • 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. 

How effective are diaphragms and caps?

If they are used correctly, diaphragms and caps are 92-96% effective: 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.

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.

Who can use diaphragms and caps?

Diaphragms are suitable for most women. But some women can be allergic to rubber or spermicides or may have other conditions which prevent a diaphragm being used. Check with your doctor or nurse to see if a diaphragm with spermicide will suit you.