An intrauterine device (IUD) is a type of birth control. It is a small, plastic device that is inserted and left inside the uterus to prevent pregnancy.
Two IUDs are available in the United States: the hormonal IUD and the copper IUD. The hormonal IUD must be replaced every 5 years. The copper IUD can remain in your body for as long as 10 years.
The IUD is more effective than most other forms of birth control. However, the IUD does not protect against sexually transmitted diseases (STDs) (see the FAQ How to Prevent Sexually Transmitted Diseases).
The hormonal IUD releases a small amount of the hormone progestin into the uterus. Progestin thickens the cervical mucus, which decreases the chance that the sperm will enter the cervix. It may make the sperm less active. It also thins the lining of the uterus. This keeps a fertilized egg from attaching and makes menstrual periods lighter.
The copper IUD releases a small amount of copper into the uterus. The copper can prevent the egg from being fertilized or attaching to the wall of the uterus. The copper also prevents sperm from going through the uterus and into the fallopian tubes and reduces the sperm's ability to fertilize an egg.
Some women may not be able to use an IUD. The size or shape of a woman's uterus may not be compatible with the IUD. Women who have had a recent abnormal Pap test result or other conditions should not use an IUD.
Your health care provider must insert and remove the IUD. The IUD often is inserted during or right after your menstrual period. The IUD is put in a long, slender, plastic tube. The tube is placed into the vagina and guided through the cervix into the uterus. The IUD is then pushed out of the plastic tube into the uterus. The IUD springs open into place, and the tube is withdrawn.
Insertion of the IUD does not require anesthesia (pain relief), although you may have some discomfort. Taking over-the-counter pain relief medication before the procedure may help. Sometimes a health care provider will use local anesthesia to insert the IUD.
Once the IUD is inserted, your health care provider will show you how to check that it is in place. Each IUD comes with a string or "tail" made of a thin plastic thread. After insertion, the tail is trimmed so that 1-2 inches hang out of the cervix inside your vagina.
It is important to check the tail regularly. To do this, you must insert a finger into your vagina and feel around for the tail. You can do this at any time, but doing it right after your menstrual period is easy to remember. If you do not feel the tail or if you feel the IUD, call your health care provider. The IUD may have slipped out of place. Use another form of birth control until your IUD is checked. If you can feel the IUD, see your health care provider. Do not try to remove it yourself.
Local Anesthesia: The use of drugs that prevent pain in a part of the body.
Pap Test: A test in which cells are taken from the cervix and vagina and examined under a microscope.
Progestin: A synthetic form of progesterone that is similar to the hormone produced naturally by the body. Progesterone is a female hormone that is produced in the ovaries and makes the lining of the uterus grow; when the level of progesterone decreases, menstruation occurs.
Sexually Transmitted Diseases (STDs): Diseases that are spread by sexual contact, including chlamydial infection, gonorrhea, genital warts, herpes, syphilis, and infection with human immunodeficiency virus (HIV, the cause of acquired immunodeficiency syndrome [AIDS]).
Uterus: A muscular organ located in the female pelvis that contains and nourishes the developing fetus during pregnancy.
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