Thrombosis and oral contraceptives: possible predisposition.

Area of Science:

• Vascular Medicine
• Hematology
• Pharmacology

Background:

• Combined oral contraceptives (COCs) are associated with an increased risk of venous thromboembolism (VTE).
• Previous thrombosis history in women using COCs warrants investigation into underlying hemostatic abnormalities.
• The fibrinolytic system plays a crucial role in clot resolution and preventing thrombosis.

Purpose of the Study:

• To investigate coagulation and fibrinolytic system components in women with a history of thrombosis using COCs.
• To assess the fibrinolytic activator content in superficial vein walls.
• To evaluate the utility of antithrombin III concentration in identifying thrombosis predisposition.

Main Methods:

• Analysis of coagulation factors and fibrinolytic system components in 31 women with prior phlebographically-verified thrombosis.
• Histochemical determination of fibrinolytic activator content in superficial vein biopsy specimens.
• Measurement of antithrombin III concentration.

Main Results:

• Most patients exhibited pathological changes, particularly within the fibrinolytic defense system.
• Fibrinolytic system abnormalities suggest a potential predisposition to thrombosis.
• Normal antithrombin III concentrations were observed in all patients.

Conclusions:

• Women with a history of thrombosis may have underlying fibrinolytic system defects, potentially predisposing them to VTE independently of COCs.
• Antithrombin III level measurement is not a reliable marker for identifying individuals predisposed to thrombosis.
• Oral contraceptives should be avoided in women with a history of thrombosis and potential fibrinolytic abnormalities.