Effect of short term use of oral contraceptives on fibrinolytic activity of the blood

2 oral contraceptives (Primovular 21 and Deoleuton 21) caused a statistically significant lowering of the blood fibrinolytic activity in 14 of 20 women after only 1 month of treatment. It is suggested that this finding may prove of considerable importance for early detection of cases which may be prone to thrombotic episodes.