Diaphragm
The diaphragm is a dome-shaped latex cap that is first coated with a spermicidal gel or cream and then placed high in the vagina before intercourse. It is a physical barrier to sperm entering the cervix but, more importantly, it holds the spermicidal cream or gel against the cervix and thus immobilizes sperm near the cervical canal.

Effectiveness
Failure rates among all users (including those not using the method correctly) are about 20%. However, among conscientious users, failure rates may be as low as 5%.

Fitting
Diaphragms come in different sizes and rim types. They are available by prescription and need to be fitted by a clinician. After insertion, it is important to check that the diaphragm covers the cervix. Diaphragms may need to be refitted if there has been a pregnancy, large weight change, or discomfort with use. Neither partner should be aware of a properly fitting diaphragm.

Proper Use
Apply about a tablespoon of spermicidal gel or cream into the dome of the diaphragm and spread a little around the rim. Insert the diaphragm up to 6 hours before intercourse and leave it in at least 6 hours (but no more than 24 hours) after intercourse. Do not remove the diaphragm for subsequent intercourse - just insert more spermicide with a plastic applicator.

Advantages
The diaphragm is a mechanical method and has none of the systemic side effects of the hormonal methods

Disadvantages
Barrier methods require conscientious users for consistent and correct use. For some women, the diaphragm may predispose to urinary tract infections, yeast infections and possibly bacterial vaginosis. Any substance containing petroleum jelly such as Vaseline may deteriorate the latex of the diaphragm. Using spermicides with nonoxynol-9 promotes skin irritation and possible increase in sexually transmitted diseases. In rare cases, a woman or man may be allergic or sensitive to the latex in the diaphragm.