Both diaphragms and cervical caps are known as barrier methods of contraception. They act as a barrier to keep the sperm from reaching the woman's egg (ovum) so that it can't fertilise it. Both can give some protection against some sexually transmitted diseases.

What are diaphragms and caps?
A diaphragm is a soft circular rubber dome that a woman inserts high into her vagina, covering the opening of the womb (cervix).

A cervical cap is like a diaphragm, only smaller and usually made from a stronger rubber. The cervical cap is held in position by suction. They are usually inserted higher up in the vagina than the diaphragm, directly over the cervix, which makes the cap more difficult to manage.

Diaphragms and caps come in various sizes. The size and type can be decided by your doctor or family planning clinic. The diaphragm or cap will need to be fitted by your doctor or at the family planning clinic and you will be instructed how to insert it and remove it. You should also have a practice at inserting and removing it yourself.

How are they used?
To use them, you need to feel comfortable about inserting your finger into your vagina and touching your genitals.

They should be used with spermicidal cream or jelly and left in place for at least 6 hours after sex but for no longer than 24 hours or 12 hours during your period. They must not be used in conjunction with petroleum jelly (Vaseline), baby oil or other oil-based products, which may damage the device.

Some people find them messy and fiddly. They can increase the risk of urinary tract infections and can cause irritation if you or your partner are sensitive to the rubber or spermicides.

If they are properly fitted, you shouldn't have any pain. You should see your doctor if you do have pain; your diaphragm or cap starts to slip; you've been pregnant or you've had a weight change of more than 3 kg.

When you have sex
You can put your diaphragm or cap in place up to 2 hours before sex, so there is no need to interrupt sexual enjoyment. Before sex, insert your diaphragm or cap with about a teaspoon of spermicidal cream or jelly, which should be spread around the rim and the centre of the dome of the device. After intercourse wait at least 6 hours before removing your diaphragm or cap.

If you have intercourse again within the 6 hours you must apply more spermicide without removing the diaphragm or cap. When you remove your diaphragm or cap, wash it with soap and water. Check each time for holes or thinning in the rubber. If you find a hole, you will need a new diaphragm or cap. Store your diaphragm or cap in a place where you can easily find it each time—a cool place is best.

You should have your diaphragm or cap checked:

What are the advantages of using a diaphragm or cap?

What are the disadvantages?

How effective are diaphragms and caps at preventing pregnancy?
The failure rate of diaphragms varies from 10-18 per cent in the first year to 4-8 per cent over a longer term. However, their effectiveness depends on proper use, experience and correct fitting. The failure rate of the cervical cap tends to be similar to that of a diaphragm, but higher in women who have had children.

If properly cared for, your diaphragm or cap should last for a year or more. Clean, dry and store it in a cool place after use and check regularly for holes by holding it up against the light or filling it with water.