Effects of two combined monophasic and triphasic ethinylestradiol/ gestodene oral contraceptives on natural inhibitors and other hemostatic variables

Abstract

Objective To evaluate the effects of two preparations of combined oral contraceptives

(COCs), the monophasic COC containing 30 μg ethinylestradiol and 75 μg gestodene and the triphasic COC containing 30/40/30 ethinylestradiol and 50/70/100 μg gestodene on seven natural inhibitors and hemostatic variables.

Method Forty-four healthy young women, randomly allocated into two groups (A and B) received the two preparations of COCs, respectively. The following variables were tested in a basic examination and at 1-, 3-and 6-month intervals to evaluate the role of the above preparations on the hemostatic balance of prothrombin time, fibrinogen, antithrombin III activity, protein C activity, total protein S antigen, plasminogen activity and lupus anticoagulant.

Results Group A women presented shorter prothrombin time at 6 months, an increased fibrinogen level at 3 months, no influence on the anticoagulant factors, antithrombin III, protein C and total protein S and an increased plasminogen activity at the 1st and 3rd months of treatment. On the other hand, group B women presented shorter prothrombin time at 3 months, no increase in fibrinogen, a decrease in antithrombin III activity and total protein S activity at the 6th month, whereas protein C and plasminogen activities were found to be increased at the 3rd and 1st, 3rd and 6th month, respectively.

Conclusions The study did not find differences between the two treatment groups, for the evaluated parameters. This finding is clearly important in the light of the recent epidemiological reports on third-generation COCs. However, differences were found among the various periods of administration of both COCs.

Key Words:

• Oral contraceptives
• Venous thromboembolism
• Hemostasis
• Hemostatic variables
• Natural inhibitors