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Intrauterine Device (IUD)

What is an intrauterine device (IUD)?

The intrauterine device (IUD) is a birth control device which is inserted into the uterus by a health care provider. The IUD is made of a plastic rod with two arms and a string.  There are two types of IUDs available in the United States: copper and progestin (hormone) IUD. 

How well does the IUD work?

The IUD is one of the most effective forms of birth control. It is over 99% effective at preventing pregnancy.

How is it used?

Your health care provider will insert the IUD into the uterus through the vagina and cervix (opening of the uterus). It only takes a few minutes to insert an IUD. Many providers give pain medicine first. Some women have cramps and spotting for a few hours after insertion.

You should be able to feel the IUD string in your vagina. Check the string once a month. If you don’t feel the string you should call your health care provider.

The copper IUD can also be used for emergency birth control. It can be inserted up to five days after unprotected intercourse. Studies have shown it to prevent pregnancy 99.9% of the time when it is used in this way. The IUD can then be left in place for up to 10 years.

What are the benefits?

The benefits of an IUD are:

  • It is 99% effective as a method of preventing pregnancy.
  • No need to think about birth control before or during sex.
  • Replacement is required just every 5 to 10 years, depending on the type.
  • The progesterone-containing IUD decreases menstrual cramps and bleeding.
  • Safe to use while you are breastfeeding.
  • Works better than the pill, patch, ring or shot.

What is the difference between the two types of IUDs?




Brand Name



When does the IUD start working?

The copper IUD starts working right away.

The progestin IUD starts working 7 days after it is inserted. You will need to use condoms or another back up method of birth control for the first 7 days after the IUD is inserted to prevent pregnancy.

How long does it work? 

10 years

5 years

Does it contain hormones?


Yes: low dose of progestin (no estrogen)

Side Effects

Heavier periods

Cramping for the first few months after it is inserted.

Cramps with your period.

Spotting and cramping for the first few months after insertion.

No period after a few months – this is not risky, and many women like it

Less common: bloating, nausea, headaches, breast pain

What are the risks?

Serious problems with the IUD are rare, and most happen within the first few days. The possible risks of IUD placement include infection, bleeding, allergic reaction, perforation of (poking a hole in) the uterus, and expulsion (falling out) of the IUD.

IUDs do not protect against sexually transmitted infection. Use latex or polyurethane condoms for protection against these infections.

Who can use an IUD?

IUDs can be safely used by most women for pregnancy prevention, including women who have not had children, as well as teens.

IUDs can be inserted at anytime during the menstrual cycle. In other words, you do not need to be on your period to have an IUD inserted.

Women with heavy periods or painful cramps during their period may benefit from use of the progestin IUD, which has been shown to improve these symptoms.

Who should not use an IUD?

You should not use an IUD if:

  • You have cancer in the uterus or cervix.
  • You have unexplained vaginal bleeding.
  • You may be pregnant.
  • You have a sexually transmitted infection.
  • You should not use a copper IUD if you are allergic to copper.

When should I call my health care provider?

Call your provider if you:

  • Cannot find the IUD string or if you feel the hard plastic of the IUD.
  • Have vaginal discharge with a bad odor.
  • Have severe, unexpected pain in your lower abdomen, especially if it happens when you have intercourse.
  • Have a fever with no apparent cause or missed a period.
  • Think you might be pregnant with the IUD still inside the uterus.
  • Want to have the IUD removed.

What happens when I want to get pregnant?

Most women get pregnant quickly after a medical provider removes the IUD.