Evolution of antithrombin activity and plasma fibrinogen levels and of hematologic values among women in child-bearing age on treatment with the new hormonal oral contraceptives

To study the evolution of antithrombin (AT) and plasma fibrinogen levels and of hematologic values among women in child-bearing age on treatment with the new hormonal oral contraceptives (HOC): in microdose, ultramicrodose and Diane-35. Retrospective review of 100 randomized cases out of a total registry of 1,245 clinical records. The mean age in our series was 23.4 years (range: 18-39 years). The mean study time was 3.3 years (range: 1-5 years). During the study period, there was not a single woman with an AT lower than 70%. There were no significant changes at the end of the study period regarding AT, plasma fibrinogen, hematocrit, hemoglobin, prothrombin activity and activated partial thromboplastin time. A significant decrease was observed for platelet count (246,113 5,842 vs. 215,636 4,383 platelets/mm3; p = 0.003). There was not a single case of thrombocytopenia registered. No relevant differences were observed between the treatment groups with microdosaged, ultramicrodosaged and Diane-35. At mid-term (3.3 years), the new HOC (in microdose, ultramicrodose and Diane-35), do not cause significant changes in AT, plasma fibrinogen, hematocrit, hemoglobin, prothrombin activity and activated partial thromboplastin time. In our series, a moderate but significant decrease in the platelet count was observed but there were no cases of thrombocytopenia. The effect of the different new HOC on the studied parameters was similar.