Effect of Oral Contraceptives on Haemostasis Variables

Abstract

!ntroduction minimal changes (avoiding the interpretation) (8).During the second meeting in Amsterdam in 1995 it was even more obvious that the haemostasis variables as intermediate indicators or "beacons" werc not adequate and Vandenbroucke stated "Now we have lost confidence,in the intermediate

Oral Contraceptives and the Risk of Venous Thrombosis

“…[1][2][3][4] Potential prothrombotic effects included increases in the levels of coagulant factors and decreases in the levels of the anticoagulant proteins antithrombin and protein S. However, these changes were believed to be at least partially counterbalanced by such antithrombotic effects as increases in the levels of other anticoagulant proteins and increased fibrinolysis. Furthermore, the levels of coagulation factors typically remained within the normal range during oral-contraceptive use.…”

“…Furthermore, the levels of coagulation factors typically remained within the normal range during oral-contraceptive use. [1][2][3][4] New studies of the effects of second-generation and third-generation oral contraceptives on the pro-coagulant, anticoagulant, and fibrinolytic pathways, in contrast, indicate that oral contraceptives have a net prothrombotic effect. Quantitatively, the effect is greater with preparations that confer a higher risk of thrombosis.…”

“…[1][2][3][4]83 It is not known whether enhanced fibrinolytic activity during oral-contraceptive use has clinical implications, since changes in the fibrinolytic system have not been demonstrated to affect the risk of venous thrombosis. One antifibrinolytic mechanism involves thrombin-activatable fibrinolysis inhibitor (TAFI), which, when activated, inhibits fibrinolysis by removing from fibrin the lysine residues that are essential for the binding and activation of plasminogen.…”

“…These lower-estrogen contraceptives were considered safer: changes in hemostatic factors remained small, inconsistent in direction, and mostly within the normal range. [1][2][3][4] Recent studies have challenged the concept that reducing the dose of estrogen in oral contraceptives eliminates the risk of venous thrombosis. These studies have included epidemiologic data suggesting that certain progestins may increase the risk of thrombosis associated with low-estrogen preparations, new findings regarding individual genetic susceptibilities to the thrombogenic effect of oral contraceptives, and new insights into the hemostatic changes that predispose women to thrombosis.…”

Guidelines on fibrinogen assays

“…Some tests are designed for emergency situations, where an exact fibrinogen level may not be required but merely an estimate of whether the levels are normal or grossly decreased. The expanded range of coagulation automation and reagents has had a varying impact on the performance of laboratory (Eliasson et al, 1993;Hantgan et al, 1994;Lowe et al, 1997;Kluft & Lansink, 1997;van der Bom et al, 1997;Humphries et al, 1999). tests and their precision.…”