What is a Diaphragm?

The diaphragm is a small, dome shaped rubber cup that fits inside the vagina, covering the cervix (the entrance to the uterus). The diaphragm is intended for pregnancy prevention, but offers little protection against STD’s.

How does it work?

The diaphragm is filled with spermicidal cream or jelly that will kill any sperm that it comes in contact with. The spermicide also assists in making a seal between the diaphragm's rim and the vaginal walls, creating a barrier between the outer vagina, sperm and semen and the cervix, uterus and eggs. This barrier is what prevents fertilization and pregnancy from occuring. The diaphragm is inserted prior to intercourse and remains effective for up to 6 hours. If a longer time has elapsed, then fresh spermicide, inserted into the vagina with an applicator may be used. This is done without the removal of the diaphragm. After intercourse the diaphragm must be left in place for at least 6 hours, but should not be left in for longer than 24 hours due to the possible risk of toxic shock syndrome.

Do you need a prescription?

The woman must be fitted for a diaphragm by a doctor or nurse practitioner as diaphragms come in slightly different sizes. A water tight seal must be made between the diaphragm’s rim and the vaginal walls for the diaphragm to be effective.

How effective is it in preventing pregnancy?

The failure rate for the diaphragm during the first year's use is 18%. For the perfect user, who is very careful every time, it is 6%. The person who is at high risk for becoming pregnant using the diaphragm is one who has frequent intercourse (more than 3 times per week), and one who is less than 30 years old.

Risk Factors

The diaphragm does not cause any systemic side effects and does not alter the woman’s menstrual cycle. There is a minor risk of toxic shock syndrome if the diaphragm is left in place for longer than 24 hours.


Diaphragms bought in a pharmacy are approximately $22. In a clinic they cost less, approximately $10 to $15. They should be replaced every 3 years or sooner if a hole has been detected in the diaphragm’s rubber.