Effect of two low-dose gestodene containing monophasic oral contraceptives on hemostasis in Bulgarian women.

OBJECTIVE

To compare the effects of two monophasic oral contraceptives upon coagulation, fibrinolysis and the system of natural inhibitors (anticoagulant pathways) in Bulgarian women.

METHODS

This prospective, open clinical study lasted 12 months and included 70 women, divided into two equal groups of 35 each. The women from group A received a contraceptive containing 20 microg ethinylestradiol/75 microg gestodene. The women from group B received a contraceptive containing 30 microg ethinylestradio l/75 microg gestodene. At the beginning and again at the end of the study, the following values were determined: prothrombin time (PT), activated partial thromboplastic time (aPTT), thrombin time (TT), fibrinogen (F), Factor VII (FVII), Factor X (FX), plasminogen, alpha 2-antiplasmin, tissue-type plasminogen activator (t-PA), D-dimers, protein C (Pr C), total Protein S (TPr S), antithrombin III (AT III) and heparin Cofactor II (HC II).

RESULTS

We did not find any statistically significant differences in the global tests of hemostasis (PT, aPTT, TT) in either group compared with the baseline values. At the end of the study there was an increase in the levels of fibrinogen, FX, PrC and H II, and also diminution of t-PA in both groups in comparison with the baseline values. At the end of the study the activity of FVII, alpha2-antiplasmin and AT III was elevated only in group B. Although certain alterations in hemostasis parameters were observed, all of them were within the reference range. We did not observe or suspect any cases of vascular, thrombotic or other incidence in the observed groups of 840 cycles of hormonal contraception over the 12-month period.

CONCLUSION

There is an increase in both procoagulant and fibrinolytic activity when using low-dose gestodene containing monophasic oral contraceptives. This can be interpreted as a shift to a higher equilibrium. There is no need for screening for thrombofilia in healthy, non-obese, non-smoking Bulgarian females, aged between 18 to 35 years, without a personal or family history of thrombotic diseases, before starting on third generation oral contraceptive with gestodene.