Benefits and Contraindications of Intrauterine Devices (IUDs) for Birth Control

Approximately fifty percent of pregnancies in the United States are unplanned despite the fact that there are numerous birth control options available to women. Intrauterine devices or IUDs are the most common form of reversible contraception used worldwide. IUDs are a great option for women who want long-term birth control that is reversible and not associated with the side effects of systemic hormonal contraceptives such as oral birth control pills and the injectable Depo Provera.

IUDs are extremely effective. In fact, they offer protection from pregnancy that is equal to a tubal ligation. In the first year of use the pregnancy rate is 0.1 to 0.8 percent for IUDs as compared to birth control pills which have a first year pregnancy rate of 8 percent. IUDs protect from pregnancy for 5 to 10 years depending on the type of IUD.

Intrauterine devices are placed in the uterus and, when ready, removed from the uterus through a simple in-office procedure performed by a physician. IUDs require minimal effort from the user. In fact, once the IUD is placed the only effort a woman has to make is to feel that the IUD strings are still in place once a month after menses. As an additional benefit, after two to three years of use, an IUD is actually cheaper than oral contraceptive pills.

Two of the most popular IUDs are the Mirena and the Paragard. The Mirena IUD lasts up to 5 years and releases a small amount of levonorgestrel (progesterone) locally at the cervix. This hormone prevents pregnancy by thickening the cervical mucus so that sperm cannot pass through. The hormone additionally thins the uterine lining so that it is difficult for eggs to implant.

The Paragard IUD, on the otherhand, is a copper IUD. Paragard lasts up to 10 years and prevents pregnancy by the sperm-killing effects of copper as well as by causing a local foreign body inflammatory response.

Unfortunately, some women are NOT good candidates for an IUD. This includes:

-women with a history of PID or endometritis in the past three months

-women with severe uterine anatomical abnormalities

-women with cervical or uterine cancer

-women with a history of ectopic pregnancy

-women with gestational trophoblastic disease

-for Mirena only, women with liver disease or with breast cancer

-for Paragard only, women with Wilson's disease

IUDs are safe and effective methods of birth control for women who desire a long-term birth control option that is not permanent. However, some women are not good candidates and IUDs are associated with certain side effects, thus any woman interested in IUD use should work with her physician to determine which means of birth control is best for her individual needs.

References:

McCarthy, L. Levonorgestrel-Releasing Intrauterine System (Mirena) for Contraception. Am Family Physician. May 2006-73(10): 1800-1801.

Package Inserts (available online at Paragard.com and Mirena.com)

Thonneau PF. Contraceptive efficacy of intrauterine devices. Am J Obstet Gynecol. March 2008-198(3): 248-53