Blood coagulation with a combination pill containing gestodene and ethinyl estradiol.

The coagulation effects of oral contraceptives are determined by the interaction of the estrogen and the progestogen components. Serial studies on the coagulation system were carried out in 120 randomly allocated healthy women to compare the effects of (1) triphasic gestodene/ethinyl estradiol and triphasic levonorgestrel/ethinyl estradiol and (2) monophasic gestodene/ethinyl estradiol and monophasic desogestrel/ethinyl estradiol. The triphasic study showed significant increases in factor VII, factor X, fibrinogen, plasminogen, and fibrinolytic activity. No significant differences were noted between levonorgestrel and gestodene except for factor VII, which was higher with gestodene. Antithrombin III and anti-Xa were unchanged, and platelet aggregation was slightly accelerated with gestodene. The monophasic study is still in progress: Significant increases of factor VII, factor X, plasminogen, and fibrinolytic activity and no changes in antithrombin III, anti-Xa, and platelet aggregation have been found with both monophasic gestodene and desogestrel. The results of the triphasic study indicate that the effect of gestodene on the blood coagulation system is similar to that of levonorgestrel and that both formulations increase fibrinolytic activity. The increased coagulation activity would appear to be counteracted by enhanced fibrinolysis, so protecting the dynamic balance between coagulation and fibrinolysis. Further data are required in the monophasic gestodene and desogestrel study before any conclusions can be drawn.