Intrauterine device (IUD)

The intrauterine device, or IUD, is used to prevent pregnancy. It is one of the safest and most effective reversible methods of birth control for women. IUDs are small devices made of flexible T-shaped plastic with a string on the end. A healthcare provider places the IUD into the uterus through the cervix. Once the IUD is in place, a woman usually does not have to worry about getting pregnant until it is removed.

The IUD prevents pregnancy by changing the physical environment of the reproductive tract. It also causes cervical mucus to be thicker, making it harder for the sperm to move and reducing the chance of an egg being fertilized.

There are two types of IUDs available in the United States. One is coated with copper, and can stay in place and be effective for up to 10 years. Another contains hormones that are slowly released each day. It is effective for five years before needing to be replaced.

IUDs today are much safer than the ones used several years ago. Those older IUDs are no longer available. They caused pelvic infections and infertility. These complications are rare with the newer IUDs.

The IUD is safe to use when breastfeeding and is safe to use when the pill cannot be used.

The IUD does not protect a woman from sexually transmitted diseases. Women with more than one sex partner should consider another form of birth control. An IUD should not be used if a woman is allergic to copper (in regard to copper IUD), has unusual vaginal bleeding, an abnormal pap test, an infection, or is pregnant.

A provider will insert the IUD into the uterus through the cervix (opening of the uterus). The IUD is usually inserted during a menstrual period, when the cervix is slightly open and the woman is least likely to be pregnant. It takes only a few minutes to insert an IUD. Some cramping pain may be felt when the IUD is being inserted.

Following the placement of an IUD into the uterus, there may be some cramps for a couple of hours and some spotting. Some women spot for 2 weeks and some may have heavy periods. This is not as common with the hormone type of IUD. The string attached to the IUD will hang out from the cervix. It should be checked often during the first few months.

The failure rate of hormone type IUDs is about 1 to 2 percent. There is a higher risk of having a tubal pregnancy in women who get pregnant when an IUD is in place. Women who believe they might be pregnant should have their IUD removed. There is an increased chance of miscarriage if the IUD is left in place while pregnant. Other problems include increased menstrual bleeding and cramps (with the copper IUD), mostly during the first few months of use, spotting between periods, and less common problems include embedding of the IUD in the uterine wall and perforation of the uterus by the IUD. Bleeding may be irregular or absent with the progesterone-containig IUD.

As a safety precaution after every menstrual period, women should check for the string attached to their IUD. Seek medical evaluation should any of the following occur:

• severe cramping
• unusual bleeding
• the string cannot be felt
• fever without another cause
• bad-smelling discharge
• late period or (if using copper IUD)
• the hard plastic of the IUD can be felt

Last Reviewed 2008

Disclaimer: This content is reviewed periodically and is subject to change as new health information becomes available. The information provided is intended to be informative and educational and is not a replacement for professional medical evaluation, advice, diagnosis or treatment by a healthcare professional.

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