Overview

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. If you and your doctor discuss it before you give birth, this can be done right after you have your baby.

You are using either a hormonal IUD or a copper IUD.

• Hormonal IUDs prevent pregnancy for 3 to 5 years, depending on which IUD is used. But your doctor may talk to you about leaving it in for longer. Once you have it, you don't have to do anything else to prevent pregnancy.
• The copper IUD prevents pregnancy for 3 to 10 years. But your doctor may talk to you about leaving it in for longer. Once you have it, you don't have to do anything to prevent pregnancy.

The IUD usually stays in the uterus until your doctor removes it.

How well does it work?

The IUD is a highly effective method of birth control.

• When using the hormonal or copper IUD, fewer than 1 woman out of 100 becomes pregnant in the first year.^{footnote 1}
• 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 women who have not had a baby.

Advantages of IUDs include cost-effectiveness over time, ease of use, lower risk of ectopic pregnancy, and no interruption of foreplay or intercourse.^{footnote 2}

Other advantages of the hormonal IUD

Also, the hormonal IUD:

• Reduces heavy menstrual bleeding by an average of 90% after the first few months of use.^{footnote 2}
• Reduces menstrual bleeding and cramps and, in many women, eventually causes menstrual periods to stop altogether. In this case, not menstruating is not harmful.
• May prevent endometrial hyperplasia or endometrial cancer.
• May effectively relieve endometriosis and is less likely to cause side effects than high-dose progestin.^{footnote 3}
• Reduces the risk of ectopic pregnancy.
• Does not cause weight gain.

What are the risks?

Risks of using an intrauterine device (IUD) include:

• Menstrual problems. The copper IUD may increase menstrual bleeding or cramps. You may also have spotting between periods. The hormonal IUD may reduce menstrual cramps and bleeding.^{footnote 4}
• Perforation. In 1 out of 1,000 women, the IUD will get stuck in or puncture (perforate) the uterus.^{footnote 4} Perforation is rare, but when it occurs, it's almost always during insertion. The IUD should be removed if the uterus has been perforated.
• Expulsion. About 2 to 10 out of 100 IUDs are pushed out (expelled) from the uterus into the vagina during the first year. This usually happens in the first few months of use. Expulsion is more likely when the IUD is inserted right after childbirth or in a woman who has not carried a pregnancy.^{footnote 4} When an IUD has been expelled, you are no longer protected against pregnancy. If you think your IUD has been expelled, use a backup birth control method until you can see a health care provider.