Fibrinolytic activity. Changes induced with oral contraceptives.

Abstract

14 women who had been using oral contraceptives from 6 weeks to 70 months were tested for fibrinolytic activity. Fibinolytic activity was tested from blood plasma using a fibrin plate (Hyland method). The plasma was incubated on the plate and the resulting diameters of the lysis zones were measured. The results were plotted against those of a normal population. 86% of the subjects showed an increase in fibrinolytic activity. The range of the increase was from 12 to 70% of normal. The data leads the authors to believe that the increase in the fibrinolytic activity is a counterbalance to the increase in clotting factors and possible hypercoagulability in women using the pill. Care should be taken to check women for an increase in fibrinolytic activity when oral contraceptives are prescribed. If no increase occurs women should be removed from its use to prevent an increased risk of thromboembic complications.