The diaphragm is a birth control (contraceptive) device that prevents sperm from entering the uterus. The diaphragm is a small, reusable rubber or silicone cup with a flexible rim that covers the cervix. Before sex, the diaphragm is inserted deep into the vagina so that part of the rim fits snugly behind the pubic bone. The diaphragm is effective at preventing pregnancy only when used with spermicide.

When used with spermicide, the diaphragm helps prevent pregnancy. Among various benefits, the diaphragm:

• Allows prompt return to fertility
• Can be used as a backup method of birth control because it's effective immediately after insertion
• Can be used during breast-feeding beginning six weeks after childbirth
• Can be inserted up to six hours before sex and left in place for up to 24 hours
• Doesn't require that your partner use or wear anything for contraception
• Has few if any side effects

The diaphragm isn't appropriate for everyone, however. Your doctor may discourage use of the diaphragm if you:

• Are allergic to silicone, latex or spermicide
• Are at high risk of or have HIV/AIDS
• Are at high risk of pregnancy — you're younger than age 30; you have sex three or more times a week; you've had previous contraceptive failure with vaginal barrier methods; or you're not likely to consistently use the diaphragm
• Have vaginal abnormalities that interfere with the fit, placement or retention of the diaphragm
• Have a vaginal or pelvic infection
• Have frequent urinary tract infections
• Have a history of toxic shock syndrome
• Have significant pelvic organ prolapse, such as uterine prolapse — when the uterus descends into the vagina from its normal position in the pelvis

The diaphragm doesn't offer reliable protection from sexually transmitted infections (STIs).

When using a traditional diaphragm, an estimated 12 out of 100 women will get pregnant in the first year of typical use of the diaphragm. And an estimated six out of 100 women will get pregnant during the first year of use when following usage instructions exactly.

For a newer type of diaphragm — the Caya diaphragm — pregnancy rates are slightly higher, with an estimate that around 17 out of 100 women will get pregnant after one year of typical use.

Consistent and correct use is essential to the effectiveness of either type of diaphragm. For example, you may get pregnant when using a diaphragm if:

• You don't use the diaphragm every time you have sex
• The diaphragm becomes dislodged from the cervix during sex
• You don't use spermicide
• You remove the diaphragm within six hours after having sex

Spermicide applied to the diaphragm may damage the cells lining the vagina, causing:

• Increased risk of contracting STIs
• Vaginal irritation
• Urinary tract or vaginal infection

Contact your health care provider if:

• The diaphragm slips out of place when you walk, sneeze, cough or strain
• You notice blood on the diaphragm after you remove it that isn't related to your period
• You or your partner experiences pain during or following use of the diaphragm
• You have signs or symptoms of toxic shock syndrome, such as a sudden high fever, diarrhea, dizziness, vomiting, fainting or a rash that looks like sunburn
• You're unable to remove the diaphragm

The traditional dome-shaped diaphragm comes in different sizes, and you need to be fitted for one by your health care provider. A newer diaphragm option — the Caya diaphragm — comes in one size. To get either type of diaphragm, you need a prescription from your health care provider.

During an office visit, your health care provider will demonstrate how to insert and remove the diaphragm — and may have you practice doing so, too. To confirm that the diaphragm is in the correct position, your health care provider may perform a pelvic exam.

Before you use the diaphragm for the first time, practice inserting the diaphragm until you're comfortable with it. You may want to use a backup method of contraception, such as a male condom, the first few times you use the diaphragm.

Always use the diaphragm with spermicidal cream, foam or gel. Avoid use of body lotions near your vagina and vaginal medications when using the diaphragm. If you're using a diaphragm and douche, wait until at least six hours after sex to avoid washing away spermicide.

Make sure you regularly check your diaphragm for puncture marks or cracks. To search for holes, hold your diaphragm up to the light and gently stretch the rubber between your fingers or fill the diaphragm with water. Replace your diaphragm at least every two years. You may need to have your diaphragm checked and possibly refitted if:

• Your diaphragm no longer fits snugly or comfortably
• You've given birth or had an abortion
• You've had pelvic surgery
• You've gained or lost more than 10 pounds (4.5 kilograms)
• You have repeated urinary tract infections
• You or your partner feels pain or pressure during sex

To use the diaphragm:

• Apply spermicide. Fill the diaphragm's bowl with about 1 tablespoon (15 milliliters) of spermicide. Spread a thin layer of spermicide around the rim of the diaphragm with your finger. Use only water-based lubricants with the diaphragm.
• Insert the diaphragm. Find a comfortable position, such as standing with one foot propped up, squatting or lying on your back. Separate your labia with one hand. With the other hand, hold the diaphragm with the bowl facing upward and squeeze the diaphragm between your thumb, index and middle fingers. Slide the diaphragm into your vagina and push it along the back wall of your vagina as far as it will go. Use your index finger to push the front rim of the diaphragm up behind your pubic bone.
• Check the diaphragm's position before sex. Make sure you can feel your cervix through the soft dome of the diaphragm. After inserting the diaphragm, apply spermicide inside the vagina before each time you have sex. If the diaphragm is dislodged during sex, reapply spermicide.
• Gently remove the diaphragm. After sex, leave the diaphragm in place for at least six hours and up to 24 hours. To remove the diaphragm, hook your finger under the front rim of the diaphragm and gently pull it down and out of your vagina. If the diaphragm is difficult to remove, insert your finger between the rim of the diaphragm and your vaginal wall to break any suction. After removal, wash the diaphragm with mild soap and warm water and allow it to air-dry. Store the diaphragm in its provided container.