A 1-year study to compare the hemostatic effects of oral contraceptive containing 20 μg of ethinylestradiol and 100 μg of levonorgestrel with 30 μg of ethinylestradiol and 100 μg of levonorgestrel

Objectives: To comparatively evaluate the impact of a balanced one-third dose-reduced oral contraceptive on hemostatic variables. Methods: In an open-label, randomized study, a dose-reduced oral contraceptive containing 20 mu g of ethinylestradiol (EE) and 100 mu g of levonorgestrel (LNG) was compared with a reference preparation containing 30 mu g of EE and 150 mu g of LNG. One-year data were obtained from 48 volunteers. Results: The direction and magnitude of the changes (increase or decrease) in most of the hemostatic variables were similar in both treatment groups. The majority of changes of all investigated variables remained within the reference ranges of variation. The procoagulatory variables increased to some extent from baseline to treatment cycle 13, while the anticoagulatory variables slightly decreased. In particular, thrombin turnover measured by prothrombin fragments 1+2 increased during treatment by 35% in the 20 mu g of EE group and by 38% in the 30 mu g of EE group. Statistically significant differences between the two treatment groups were found only for TAT. For the profibrinolytic variables, plasminogen was increased by 42% (20 mu g of EE) and 49% (30 mu g of EE). While the plasma levels of tPA antigen were reduced during treatment, the levels of its activity were increased by 54% (20 mu g of EE) and 20% (30 mu g of EE). For PAI, both antigen and activity were decreased, somewhat more pronounced with 20 mu g of EE. D-Dimer remained virtually unchanged. Finally, the median FbDP levels were elevated by 30% (20 mu g of EE) and 38% (30 mu g of EE). (c) 2005 Elsevier Inc. All rights reserved.