Intrauterine Device

September 15, 2011

The intrauterine device (IUD) is a T-shaped plastic device that is placed into the uterine cavity. It provides a woman with a continuous method of contraception. The two types of intrauterine device currently available in the United States are the copper-releasing device (ParaGard) and the hormonereleasing device (Mirena). The intrauterine device prevents pregnancy by several different proposed mechanisms. The copper in the ParaGard intrauterine device is a spermicide. The progesterone in the Mirena intrauterine device causes thickening of the cervical mucus that sets up a barrier to sperm trying to enter the uterine cavity. All intrauterine devices set up a sterile inflammatory reaction of the uterine lining, which also is lethal to sperm.

Throughout the world, the intrauterine device is a very popular choice of birth control. It is not a commonly used contraceptive in the United States because of the fear that the intrauterine device can cause serious pelvic infection. This fear stems from the history of problems associated with a particular type of intrauterine device (Dalkon Shield™) which was used in the 1970s. The Dalkon Shield™ has been off the market since 1974 and had inherent design flaws which may have been the cause of the increased incidence of pelvic infection linked with its use. The intrauterine devices that are available today are safe and effective. Although pelvic infection remains as a slight possibility with intrauterine device use, the danger is more dependent on the user’s risk factors than on the intrauterine device itself.

The intrauterine device is 99% effective in the prevention of pregnancy. It is as effective as a tubal ligation and creates less of a risk of ectopic pregnancy. Although the initial expense of this contraceptive is higher than other methods, the intrauterine device becomes very cost effective with long-term use. The initial expense includes the cost of the device itself, any necessary laboratory testing, and the office visits for the screening for and insertion of the intrauterine device. Since this device can be left in place for a considerable length of time, the ongoing cost is very low. The recommended length of use is 5 years for Mirena™ and 10 years for ParaGard™.

The intrauterine device is a very “user-friendly” approach to birth control since it does not require the woman to have to remember to use her contraceptive method. It provides immediate contraceptive protection with insertion and its effect is completely reversible with the removal of the device. Even so, the intrauterine device may not be the perfect choice for everyone. Some women may experience heavy bleeding and cramping with menstruation. This is much less common with the Mirena intrauterine device. Mirena often causes a couple of months of irregular bleeding after insertion, followed by years of very light periods, or no periods at all. Increased bleeding and cramping with a ParaGard intrauterine device can usually be managed with mild pain medications. Although the risk is small, the intrauterine device use does have the potential for pelvic infection. This is mostly true of women who are not involved in a mutually monogamous relationship, as they are at most risk for sexually transmitted infections. Safe sex practices can decrease the incidence of infection within this group. Because pelvic infection can affect future fertility, the use of the intrauterine device is generally not recommended for women who have not yet had children. This recommendation, however, is beginning to change with more information about how safe the intrauterine device is. The ideal candidate for intrauterine device use is a woman in a long-term mutually exclusive relationship, who has borne children, and desires a reversible method of birth control.

The intrauterine device can also be used as a means of emergency contraception. If, after unprotected intercourse, an intrauterine device is placed within 5 days, it can be a very effective abortifacient.

The intrauterine device must be prescribed and inserted by a qualified health care provider. This birth control method can provide a woman with an extended, effective means of contraception. Women interested in using the intrauterine device should have an honest and open dialogue with their health care provider about the risks and benefits of this method to determine if the intrauterine device is the best contraceptive choice for them.

SEE ALSO: Birth control, Pelvic inflammatory disease

Suggested Reading

  • The Boston Women’s Health Book Collective. (1998). Our bodies, ourselves for the new century. New York: Touchstone Books.
  • Hatcher, R., Trussel, J., Stewart, F., Cates, W., Stewart, G., Guest, F., et al. (1998). Contraceptive technology (17th rev. ed.). New York: Ardent Media.

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