The intrauterine device (IUD) is used to prevent pregnancy. It's a small, plastic, T-shaped device. Your doctor places the IUD in your uterus.

There are two types of IUDs. The hormonal IUD works for 3 to 8 years, depending on what brand you have. The copper IUD is approved by the U.S. Food and Drug Administration to be used for up to 10 years. But studies show that extended use of the copper IUD safely prevents pregnancy for up to 12 years. Talk to your doctor about what might be right for you. Once you have an IUD, you don't have to do anything else to prevent pregnancy.

The IUD usually stays in the uterus until your doctor removes it. You can choose to have your IUD removed at any time.

How well does it work?

The IUD is a highly effective method of birth control.

• IUDs are more than 99% effective for preventing pregnancy. That means fewer than 1 out of 100 people who use an IUD as directed will have an unplanned pregnancy.
• Most pregnancies that occur with IUD use happen because the IUD is pushed out of (expelled from) the uterus unnoticed. IUDs are most likely to come out in the first few months of IUD use, after being inserted just after childbirth, or in people who have not had a baby.

What are the risks?

Using an IUD is safe and rarely causes problems. But some possible problems include:

• Menstrual problems. The copper IUD may increase menstrual bleeding or cramps. You may also have spotting between periods.
• Perforation. This means the IUD passes through the uterine wall. Perforation is rare, but when it occurs, it's almost always during insertion. The uterus usually heals on its own after a perforation.
• Expulsion. This means the IUD moves out of place. If expulsion occurs, it usually happens in the first few months of use. Expulsion is more likely when the IUD is inserted right after childbirth or in a person who has never been pregnant.
• Unplanned pregnancy. Rarely, an unplanned pregnancy happens, especially if the IUD moves out of place. If an unintended pregnancy occurs, the IUD needs to be removed right away.