What's a diaphragm?
A diaphragm is a shallow dome-shaped rubber cup that you insert into your vagina to keep sperm from entering your cervix. If you use it perfectly every time, a diaphragm is about 94 percent effective in preventing pregnancy. But it takes some practice to insert the device correctly, and a woman using a diaphragm for birth control has about a 16 percent chance of getting pregnant during the first year of typical use. A diaphragm won't protect you against sexually transmitted diseases so use a latex condom.
Where can I get one?
You'll have to be custom-fitted for your diaphragm by a doctor or nurse-practitioner. She or he will first do a pelvic exam and then measure your cervix to determine what size your diaphragm should be (it can range from 50 to 105 millimeters across). Your doctor or nurse-practitioner can show you how to insert the diaphragm. Then you may be able to buy one in your size right there at the doctor's office or family-planning clinic, or you may need to order one from your pharmacist. It will cost between $15 and $75.
How do I use it?
You can insert the diaphragm as much as three hours before sex. First empty your bladder and wash your hands with soap and water. Then hold your diaphragm up to a light to check for tiny holes or weak spots. (Don't use it if the rubber looks worn or if any light shines through.) Spread a teaspoon or so of spermicidal jelly on both sides of the diaphragm, and especially around the rim. To make insertion easier, you can squat, lie down with your knees raised, or stand with one foot on a chair. Fold the diaphragm in half and insert it as far into your vagina as it will go. Feel for your cervix (it feels like the tip of your nose) to make sure that the diaphragm is covering it completely. If your cervix isn't covered or the diaphragm feels uncomfortable, remove it, add more spermicide, and try again.
After intercourse, leave the diaphragm in place for at least 6 hours (but not longer than 24) so that the spermicide has a chance to destroy all the sperm. (These directions apply if you're using the diaphragm during your period, too.) If you want to have sex again before 6 hours have passed, leave the diaphragm in place but insert more spermicide into your vagina with an applicator. A burning or itching in your vagina after diaphragm use may indicate that you're sensitive to the chemicals in spermicides or allergic to latex; in this case, you might want to switch to another method of birth control. Studies have found that using a diaphragm can also make you more susceptible to urinary-tract infections. To help guard against these, keep your diaphragm in for relatively short periods and urinate just before and just after intercourse.
To remove the diaphragm, hook your index finger behind the front rim and pull down and out. (Be careful not to puncture the rubber with your fingernail.) If it resists, squat and push with your pelvic muscles to break the suction between the rubber cup and your cervix, then pull the diaphragm out with your finger. After each use, wash the diaphragm with mild soap and water, let it dry, and return it to its case.
How long will a diaphragm last?
If you care for it properly, your diaphragm should last one to two years. But be sure to check for holes and thin spots each time you use it. When it starts to wear thin, it's time for a new one.
Have your doctor or nurse-practitioner check the fit of your diaphragm after you've undergone pelvic surgery, lost or gained 10 pounds or more, or had a pregnancy, abortion, or miscarriage. These things can change the size and shape of your cervix enough to make a new diaphragm necessary.
American Congress of Obstetricians and Gynecologists. Barrier Methods of Contraception. 2008
Planned Parenthood. Diaphragm. May 2010.
American Academy of Family Physicians. Birth Control: How to Use Your Diaphragm. Familydoctor.org. 2005 June.
Brigham Narins, Editor. World of Health: 307-308. The Gale Group 2000.
Hooton TM et al. A prospective study of risk factors for symptomatic urinary tract infection in young women. N Engl J Med 1996 Aug 15;335(7):468-74.