IUDs Acquitted As Threat to Fertility

Study blames infection, not birth-control device

WEDNESDAY, Aug. 21, 2001 (HealthDayNews) -- Women who use intrauterine devices (IUDs) for contraception shouldn't worry that the implants will hurt their chances of having children one day.

Researchers have found that the threat of infertility associated with IUDs is linked to other causes -- particularly chlamydia infection -- and that the devices themselves pose no threat to a woman's ability to conceive.

"Bacteria such as those transmitted sexually cause pelvic inflammatory disease and subsequent infertility. A plastic device with copper on it does not," says David Hubacher, an epidemiologist with Family Health International, a nonprofit research firm in Durham, N.C. Hubacher is the lead author of a study reported in the Aug. 23 issue of the New England Journal of Medicine.

Intrauterine contraception was once fairly common in the United States. But reports that older IUDs could cause damaging pelvic infections, and the highly publicized disaster of the Dalkon Shield -- which led to pelvic inflammation and infertility in some women -- has made them all but extinct in this country.

Still, while only about 1 percent of American women use IUDs, down from 10 percent in the 1970s, the devices are much more common in the rest of the world. In Germany and Denmark, for example, 20 percent of women use them. Globally, more than 100 million women use IUDs, making them the most popular reversible contraceptive. Their use is more widespread than birth control pills.

The first IUDs were made of plastic, but newer models include copper which in ways not yet fully understood keeps sperm from reaching descending eggs. If the eggs were fertilized, the IUD would prevent the egg from taking hold in the uterus. Implanted in the uterus for as long as 10 years, experts say the device is more than 99 percent effective at preventing pregnancy.

In fact, the researchers say copper-coated IUDs do stimulate local inflammation that is believed to increase their ability to stall sperm. However, they say this reaction clears up when the device is removed and does not appear to spark pelvic irritation that can harm the fallopian tubes.

Hubacher and his colleagues studied IUD use in more than 1,800 Mexican women, including 1,300 who were infertile and 584 who were pregnant for the first time.

Among the infertile women, 358 were diagnosed with occluded fallopian tubes, meaning their eggs were unable to pass from the ovaries into their uteruses. But they were no more likely to have used an IUD than women who were infertile from other causes, say the researchers. Nor were they more likely to have used the devices compared with the pregnant women. Duration of IUD use did not appear to be associated with tubal sterility or gynecological complications, the researchers say.

However, the study did find that women with signs of chlamydia infections were twice as likely to have blocked fallopian tubes as women not exposed to the bacteria. Since sensitive screening for the sexually transmitted disease wasn't available in the 1970s, the researchers suspect that cases of infertility then linked to IUDs were in reality the result of chlamydia, a leading cause of sterility in women.

"The primary message here is that IUDs are much safer than previously thought," Hubacher says.

Dr. Vanessa Cullins, vice president of medical affairs at the Planned Parenthood Federation of America, calls the latest findings "very, very reassuring" and says the results confirm what other recent analyses have suggested. "IUDs are very safe in individuals not exposed to sexually transmitted infections," Cullins says.

What To Do

IUDs may be a safe birth control choice for many women, but they're not for everybody. They don't prevent sexually transmitted diseases, so they're recommended only for women in mutually monogamous relationships or in addition to a condom.

If you or your partner are having sex with more than one person, use a condom.

To find out more about IUDs, try the Population Council, Planned Parenthood, or the American Medical Association.

Ortho-McNeil Pharmaceutical makes ParaGard, the most widely used IUD in the United States.

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