A comparative study of the hemostatic effects of two monophasic oral contraceptives containing 30 mu(g) ethinylestradiol and either 2 mg chlormadinone acetate or 150 mu(g) desogestrel.

Objectives: To determine the effect of two low-dose monophasic oral contraceptives containing either 2 mg chlormadinone acetate or 150 microg desogestrel on blood clotting and fibrinolysis.
Methods: In vivo markers of intravascular coagulatory and fibrinolytic activity were measured in 45 volunteers randomly assigned to a 6-month treatment with one of the two study preparations.
Results: During oral contraceptive use, the procoagulatory activity increased (increased prothrombin fragment 1+2), the anticoagulatory capacity changed (increased protein C activity, decreased activated protein C sensitivity, decreased protein S activity and decreased antithrombin III activity) and the fibrinolytic system was activated (increased concentrations of plasmin-antiplasmin complexes and D-dimer as well as total fibrin degradation products). There were no relevant differences between the two medication groups.
Conclusion: Our results demonstrate that both oral contraceptive preparations have comparable effects on the hemostatic system. There was a shift towards a new equilibrium of hemostatic activities, both coagulatory and fibrinolytic, at a higher turnover rate. Changes did not exceed the range of normal variation and were comparable to the published effects of other low-dose oral contraceptives. There was no evidence ofa differential risk of deep vein thrombosis between the two preparations.