The effects of two phasic oral contraceptives on hemostasis and platelet function.

OBJECTIVE

To compare the effects on hemostatic parameters of a combiphasic oral contraceptive containing desogestrel and ethinyl estradiol (DSG/EE) and a triphasic oral contraceptive containing levonorgestrel and ethinyl estradiol (LNG/EE).

METHODS

In an open-label, randomized, group-comparative study in 10 healthy volunteers per treatment group, the effects on parameters of coagulation, anticoagulation, fibrinolysis, antifibrinolysis and platelet function were determined at baseline, after three treatment cycles, and after a post-treatment cycle. Changes from baseline were analyzed using a paired t-test, whereas between-group differences were analyzed by means of an analysis of co-variance.

RESULTS

Both OC preparations induced modest changes of some coagulation, anticoagulation, fibrinolysis and antifibrinolysis parameters, although all mean values remained within the normal range. No significant effects were observed with either OC with respect to platelet function. Statistically significant differences between the two preparations could occasionally e observed: the concentrations of antithrombin II (AT-III) and Factor VII were higher with the DSG/EE preparation than with LNG/EE preparation at the end of treatment and AT-III activity, AT-III concentration, Factor X concentration, and plasminogen activity were higher with DSG/EE than with LNG/EE in the post-treatment cycle.

CONCLUSIONS

Combiphasic DSG/EE and triphasic LNG/EE, both OCs with a comparable amount of EE per cycle, had no clinically significant effect on the overall hemostatic balance.