The diurnal increase in euglobulin fibrinolytic activity in women using oral contraceptives and in normal women, and the generation of intrinsic fibrinolytic activity
Jespersen, J.
Thrombosis and Haemostasis 56(2): 183-188
1986
ISSN/ISBN: 0340-6245 PMID: 3101221 Document Number: 271787
This study demonstrated that the normal increase in euglobulin fibrinolytic activity (NEF) that occurs in the morning was not affected by taking oral contraceptives. 11 women taking a combined pill of 30 mcg ethinyl estradiol and 150 mcg 1-norgestrel for 21 days were compared with 15 menstruating controls. The assay for NEF involved precipitating euglobulins and assaying on bovine fibrin plates. Extrinsic tissue plasminogen activator (t-PA) was that fibrinolysis obtained after adding pure C1-inactivator. NEF was higher in women taking pills, especially during the middle of the cycle. In controls, NEF fluctuated less, but was higher during menses and in late luteal phase. t-PA variations were much less remarkable, but generally reflected the pattern seen with NEF. The only significant difference was the relatively greater increase in morning values in the pill group during beginning and end of the cycle. When the assay was repeated with the addition of flufenamate, to inactivate the C-1 inactivator, results did not differ between the 2 groups. These data do not point to any element in this fibrinolytic system that might be associated with the increased incidence of thromboembolic episodes in women taking oral contraceptives.