New York: Comparison of a contraceptive vaginal ring with an oral contraceptive suggests that the ring does not have a higher risk of causing a blood clot, researchers report in the American Journal of Obstetrics and Gynecology.

Lead investigator Dr. Mandana Rad, of the Center for Drug Research, Leiden, the Netherlands, and colleagues note that steroid use in contraception may increase the risk of blood clots, also referred to as venous thromboembolism, through effects on the liver, and that non-oral route of administration could alter this exposure.

To determine how delivery characteristics might differ between the contraceptive vaginal ring an oral contraceptive, the researchers studied 45 healthy women who were randomly assigned to use one of the drugs for 77 days. Blood samples were taken a week before the start and toward the end of treatment.

The researchers found that drug exposure to the liver administered by the vaginal ring was similar to that given via the oral contraceptive. There is no reason to believe that the thrombosis risk in ring users will be greater than that with oral contraceptives, they note. "A single vaginal ring can provide contraception for one year," Dr. Rad told Reuters Health.

"It's easy to use, a reliable contraceptive method, and to our knowledge as safe as the most well-established hormonal contraceptives.” The ring was designed for use in developing countries by the Population Council, he added.

SOURCE: American Journal of Obstetrics and Gynecology.