How effective is it? 92 to 96% effective when used correctly. Between 4 and 8 woman in every 100 will get pregnant each year using this method.
How does it work? A flexible latex or silicone dome coated in spermicide is put into the vagina to cover the cervix and prevent sperm from entering. It is also coated with spermicide to kill sperm on contact.
Advantages: Can be put in any time before sex. You only have to use it when you have sex and there are no serious health risks associated with this.
Disadvantages: Putting it in can interrupt sex and extra spermicide must be used if you have sex again. Some people can be sensitive to spermicide. Cystitis (bladder infection) can be associated with diaphragm use. It can take time to learn how to put it in.
Other facts: You need to use the correct size and can be measured by a nurse or doctor. The size you need may change after having a baby, a miscarriage or an abortion. It must be left in for 6 hours after sex.