Contraceptive: The Intrauterine Device

Effortless Option: The Intrauterine Device The exact reason is unknown, but this small object, when installed in the uterus, prevents conception with better than 95 percent reliability. The device must be inserted by a doctor, but can be left in position for at least a year. The string protruding through the cervix serves to confirm that the IUD has remained properly placed.

The intrauterine device (IUD), a small device that a doctor inserts into a woman's uterus, requires less attention than any other type of contraceptive. Once in place, it provides effortless round-the-clock protection against pregnancy. It deserves consideration by any woman who cannot take birth control pills and is unable or unwilling to use barrier methods consistently.

With the IUD, maintenance is minimal. All the woman need do is check at least once a month to make sure the device is correctly in place. A string attached to the IUD hangs down through the cervix and into the vagina. If this string can be felt with a fingertip, the IUD is still in position.

Of course, even if the IUD seems to be working fine, it periodically must be replaced: every year for the type containing a slow-release female hormone; every eight years for the type wrapped with copper wire.

Although the IUD sounds beautifully simple, it has a number of distinct disadvantages:

1. Insertion of the IUD may briefly be painful, especially for a woman who has never borne a child.

2. After insertion of the IUD, mild uterine cramps and bleeding may continue for days or even weeks.

3. An IUD may make menstrual periods both heavier and more painful.

4. An IUD increases the risk of a pelvic infection, particularly in women with multiple partners; some such infections can cause permanent sterility.

5. There is some risk that the IUD will damage the wall of the uterus.

6. If a woman gets pregnant despite the IUD, she is at increased risk of an ectopic (tubal) pregnancy, which is a life-threatening emergency.

For all these reasons, a woman should not use an IUD if she has multiple sex partners or if she has ever had a pelvic infection, a tubal pregnancy, or unexplained bleeding from the uterus.

Surprisingly, it is still uncertain how the IUD prevents pregnancy. It may work by irritating the woman's uterus, changing the uterine lining and secretions in ways that disrupt fertilization.

Women who use an IUD have a two to four percent risk of accidental pregnancy.