MONDAY, Sept. 12 (HealthDay News) -- Intrauterine devices (IUDs) may reduce a woman's risk of cervical cancer, a new study contends.

"Our data suggest that use of IUDs significantly reduces the risk of cervical cancer and that this effect does not seem to be due to differences in screening histories between users and non-users," said the Spanish researchers who authored the study.

While the study found an apparent association between IUD use and cervical cancer risk, it did not prove a cause-and-effect.

The study, published online Sept. 13 in The Lancet Oncology, said that although IUDs did not affect women's risk for HPV (human papillomavirus) infection -- the virus that causes cervical cancer -- the plastic devices inserted into the uterus may prevent HPV from progressing to cervical cancer.

In conducting what they called the largest epidemiological study to date, researchers from the Institut Catala d'Oncologia in Catalonia, Spain, examined 26 previous studies involving more than 20,000 women who were followed for a decade.

While past studies suggest that IUDs can reduce the odds of endometrial cancer, research on cervical cancer and IUDs has been mixed, the researchers said in a journal news release.

IUDs, the research showed, were associated with a lower risk of two major types of cervical cancer for up to 10 years. Women who used IUDs had a 44 percent lower risk for squamous-cell carcinoma or a 54 percent reduced risk for adenosquamous carcinoma, the study said. In the first year of use, the risk of cervical cancer was reduced by nearly half, the study authors said.

How long the women used the IUDs did not have an impact on their risk for the disease, the researchers said, and they suggested that inserting or removing the contraceptive device may destroy precancerous lesions or trigger a long-term immune response that offers protection against HPV progression.

While the IUD is a popular method of birth control around the world, just 2 percent of American women use one. The reason: many women are afraid to use an IUD because one older type -- the Dalkon shield -- posed significant health problems, including infertility, and was withdrawn from the market in 1975.

Today's IUDs are safe and more effective due to design changes, according to the American College of Obstetricians and Gynecologists.

More information

The U.S. National Institutes of Health has more on IUDs.