NEW YORK (Reuters Health) – Women with heavy menstrual bleeding may find that the levonorgestrel-releasing intrauterine system (Mirena; Bayer Schering) is more effective than oral medroxyprogesterone acetate in relieving the problem, based on results of a comparison trial.

The levonorgestrel-releasing IUD was approved last year by the US Food and Drug Administration for the treatment of heavy periods, in addition to contraception. To see how it compared with an oral progestin for this indication, Dr. Andrew M. Kaunitz at the University of Florida College of Medicine-Jacksonville and colleagues conducted a randomized trial with 165 women who regularly lost at least 80 mL of menstrual blood every cycle.

As described in Obstetrics & Gynecology for September, the women were assigned to six cycles of treatment with 10 mg oral medroxyprogesterone acetate for 10 days starting on day 16 of their cycle, or to placement of the levonorgestrel-releasing intrauterine system.

Successful treatment was defined as blood loss less than 80 mL or a reduction of more than 50% from baseline. Blood loss was measured by analysis of all collected sanitary protection used during menstruation, and the participants recorded daily menstrual bleeding on diary cards.

The success rate was 84.8% with the levonorgestrel-releasing intrauterine system compared to 22.2% in the medroxyprogesterone group, Dr. Kaunitz and colleagues report.