A Canadian, multicentre study comparing the efficacy of a levonorgestrel-releasing intrauterine system to an oral contraceptive in women with idiopathic menorrhagia.

Objectives: To evaluate the efficacy of a levonorgestrel-releasing intrauterine system (LNG-IUS) compared with a combined oral contraceptive containing 1 mg norethindrone acetate and 20 mg ethinyl estradiol (OC1/20) in reducing menstrual blood loss (MBL) in women with idiopathic menorrhagia.

Methods: A prospective, randomized, open-label study was conducted in nine centres in Canada. Healthy women over 30 years of age suffering from idiopathic menorrhagia were treated either with LNG-IUS (n = 20) or with OC1/20 (n = 19) over 12 months. The primary endpoint was the change in MBL from baseline to 12 months. Secondary endpoints included treatment success (defined as a MBL score < 100 after 12 months), hemoglobin levels, and the menorrhagia severity score.

Results: In both treatment groups, MBL decreased significantly from baseline to 12 months (P < 0.001). For the primary endpoint, the MBL score decreased significantly more in the LNG-IUS group (median from 228 to 13, mean percent change-83%) compared to the OC1/20 group (median from 290 to 72; mean percent change-68%) (P = 0.002) after 12 months. In the LNG-IUS group, 80% of subjects had treatment success compared with 36.8 % in the OC1/20 group (P < 0.009). Both treatments increased hemoglobin concentrations significantly between baseline and 12 months. The menorrhagia severity score was consistently lower in the LNG-IUS group at all study time points and was significantly lower (P = 0.045) at six months. Both treatments were well tolerated.

Conclusion: Both the LNG-IUS and the combined oral contraceptive effectively decreased menstrual blood loss in women with idiopathic menorrhagia. The overall clinical benefit was more pronounced with LNG-IUS than with OC1/20.