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IUD (Intrauterine Device for Birth Control)

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IUD (intrauterine device) facts

  • Intrauterine devices (IUDs) are a form of birth control that prevents implantation of a fertilized egg in the uterus.
  • IUDs can contain hormones that help prevent the implantation process.
  • Other types of IUDs are copper-containing IUDs.
  • IUDs must be inserted by a health-care professional in the office.
  • Side effects of IUDs depend upon the type of IUD.
  • Copper-containing IUDs can increase menstrual bleeding.
  • Some IUDs can be left in place for up to 10 years.
  • IUDs can be removed at any time by a health-care professional.
  • IUDs do not provide protection against sexually transmitted diseases (STDs).

What is an IUD (intrauterine device)?

The intrauterine device (IUD) is a small T-shaped device that is used as a method of birth control designed for insertion into a woman's uterus. Having an IUD means that changes occur in the uterus that make it difficult for fertilization and implantation of an egg. IUDs also have been referred to as "intrauterine contraception" (IUC). Some IUDs approved for use in the United States contain medications that are released over time to facilitate the contraceptive effect. An IUD is a type of long-acting reversible contraception (LARC).

IUDs have been shown to be over 99% effective in preventing pregnancy. Although IUDs are highly effective, no birth control method, except abstinence, is considered to be 100% effective.

How does an IUD work?

It is not fully understood how IUDs work. They are thought to prevent conception by causing a brief localized inflammation that begins about 24 hours after insertion. The inflammatory reaction inside the uterus attracts white blood cells, which produce substances that are toxic or poisonous to sperm. The progesterone-releasing IUDs also cause a subtle change in the lining of the uterus that impairs the implantation of the egg in the uterine wall. This type of IUD also alters the cervical mucus, which, in turn, inhibits sperm from passing through the cervix.

Medically Reviewed by a Doctor on 2/25/2016


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