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

Abstract

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 μg of ethinylestradiol (EE) and 100 μg of levonorgestrel (LNG) was compared with a reference preparation containing 30 μg of EE and 150 μg 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 μg of EE group and by 38% in the 30 μg 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 μg of EE) and 49% (30 μg of EE). While the plasma levels of tPA antigen were reduced during treatment, the levels of its activity were increased by 54% (20 μg of EE) and 20% (30 μg of EE). For PAI, both antigen and activity were decreased, somewhat more pronounced with 20 μg of EE. d-Dimer remained virtually unchanged. Finally, the median FbDP levels were elevated by 30% (20 μg of EE) and 38% (30 μg of EE).