A recently developed contraceptive ring may not only prevent pregnancy, but also protect women from contracting HIV, says a new study featured in the May issue of the journal AIDS.

Researchers from the Weill Cornell Medical College in New York are studying the effectiveness of a vaginal ring that uses anti-HIV chemicals and other natural materials already approved by the U.S. Food and Drug Administration.

The chemicals in the ring, which disable sperm and disrupt numerous stages in the HIV life cycle, are released over a 28-day period.

Brij Saxena, one of the leading researchers for the study, said the anti-HIV chemicals released from the ring raise vaginal viscosity, or thickness of mucous in the vagina, and sustain acidity (the amount of acid in an area), contributing to a toxic environment for sperm.

In the study, researchers used HIV-1, HIV-1 resistant to the drug zidovudine (Retrovir), and human T-cell lines obtained from the National Cancer Institute AIDS Research and Reference Reagents Program to test the rings. The rings were successful in preventing these HIV strains from infecting the human cells, according to the study.

Researchers said that since the ring does not use hormones, users do not have the same risk of developing breast and cervical cancers from hormone-based contraceptives. In addition, the ring will provide more options for women who have adverse side effects to hormone-based contraceptives, spermicides, or latex condoms. The ring can also be inserted at home.

Scientists involved in the study added that the same type of technology can be developed to protect against other sexually transmitted infections.

If accepted to undergo clinical trials by the FDA, the rings will be tested in human subjects. Saxena and colleagues said the preventative quality of the ring is the most effective way to tackle a viral epidemic like HIV.

For more information, see the Weill Cornell Medical School press release and the study published in the journal AIDS.