Please note: This information was current at the time of publication but now may be out of date. This handout provides a general overview and may not apply to everyone. 

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Am Fam Physician. 1998;58(9):2087-2088

See related article on intrauterine devices.

What is an intrauterine device?

An intrauterine device, called an IUD for short, is a small, plastic, T-shaped stick with a string attached to the end. The IUD is placed inside the uterus to prevent pregnancy. Your doctor can place one in your uterus in an office visit. Once in place, the IUD stays in your uterus until a doctor removes it.

How does it work?

The IUD prevents sperm from joining with an egg. It does this by making the sperm unable to go into the egg and by changing the lining of the uterus.

What are the advantages of an IUD?

The IUD has many advantages:

  • It's very effective in preventing pregnancy, because you're always protected from pregnancy and there's nothing to remember to do (for example, no pills to take).

  • It's the cheapest form of birth control in the long run.

  • An IUD can be removed by your doctor at any time.

  • It starts working right away.

  • There's a low risk of side effects.

  • Mothers who use an IUD can breast-feed safely.

  • Neither you nor your partner can feel it.

What are the disadvantages?

You may have cramps and backache for the first few hours after an IUD is put in your uterus. Some women have bleeding for a couple of weeks after the IUD is inserted, and heavy periods after that. Rarely, the uterus can be injured when the IUD is put inside.

An older kind of IUD, which is no longer available, had serious side effects, including pelvic infections and infertility (problems getting pregnant after removal). These problems are very rare with the new IUDs.

The IUD doesn't protect you from sexually transmitted diseases, such as AIDS and herpes. In fact, these infections can be more serious in women who have an IUD. In addition, the more people you have sex with, the greater your chance of getting an infection if you have an IUD. The IUD is best for women who have only one long-term sex partner. In addition, you shouldn't use the IUD if you're pregnant, if you're allergic to copper, or if you have abnormal bleeding or cancer of the cervix or uterus.

How long does the IUD stay inside?

It depends on the kind you have. The one used most often is covered in copper and can stay in your body for up to 10 years. The other kind contains a hormone called progesterone. This one must be replaced every year. Either kind can be removed by a doctor at any time if you decide to get pregnant or don't want to use it anymore.

How do I care for my IUD?

After your IUD is put in place, you may swim, exercise, use tampons and have sex as soon as you want to. At the time of each menstrual period, you should check for the string inside the vagina by inserting a clean finger in your vagina. Call your doctor if you can't feel the string or if you feel the IUD itself. Either of these could mean that the IUD is not in the right place. Call your doctor if you miss your period or if you notice any unusual fluid or odor coming from your vagina. Keep having regular check-ups every year.

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