A diaphragm is a soft, rubber cap-shaped device which acts as a barrier to prevent a man's sperm from entering a woman's uterus. In order for the diaphragm to be effective, it must be used in combination with spermicidal cream or jelly.
Spermicide is spread in the center of the diaphragm and around the rim. The diaphragm can be inserted in the vagina up to one hour before intercourse, and must remain in place for at least six hours after intercourse. If the couple wants to have sex again within the six hours, the diaphragm must stay in place but more spermicide must be added with a special plunger. To remove the diaphragm, the woman gently pulls it out.
When used properly with the spermicide cream or jelly, the diaphragm is about 90% effective. The diaphragm or the spermicide used alone is not very effective.
The proper fit of the diaphragm should be checked by a health care provider at least once a year, or if a woman has gained or lost more than 10 pounds. Also, women who have had a baby, a miscarrige or an abortion must have the size of their diaphragm checked. Size is important because if the diaphragm does not fit properly, it will not be effective in preventing pregnancy. Additionally, the user should periodically check the diaphragm by running water through it to determine if any little holes have developed. If any water leaks through the diaphragm it is not effective and should be discarded.