Combined Oral Contraceptives and the Risk of Thrombosis

Area of Science:

• Pharmacology
• Thrombosis Research
• Women's Health

Background:

• Combined oral contraceptives (COCs) are widely used reversible contraceptives.
• Despite benefits, COCs are linked to an increased risk of venous thrombosis.
• Understanding the prothrombotic mechanisms of COCs is essential for patient safety.

Purpose of the Study:

• To review the key pathogenetic mechanisms underlying thrombosis development associated with oral contraceptive use.
• To elucidate the molecular and physiological changes induced by COCs that promote clot formation.

Main Methods:

• Literature review of studies on combined oral contraceptives and thrombosis.
• Analysis of pathogenetic pathways including coagulation, anticoagulation, fibrinolysis, and endothelial function.
• Examination of biochemical and hematological markers associated with thrombotic risk.

Main Results:

• COCs alter clotting factor levels, reduce anticoagulant proteins (antithrombin, protein S), and induce resistance to activated protein C.
• Mechanisms include decreased tissue factor pathway inhibitor (TFPI), endothelial activation, and inhibited fibrinolysis.
• Hormonal effects lead to homocysteine imbalance, nitric oxide (NO) deficiency, increased blood pressure, insulin resistance, and elevated inflammatory markers (CRP, PAI-1).
• Increased platelet adhesiveness and aggregation further contribute to thrombotic risk.

Conclusions:

• COC use is associated with multifactorial prothrombotic effects impacting coagulation, fibrinolysis, and endothelial function.
• Clinicians must assess individual patient risk factors and monitor patients regularly to mitigate complications.
• Further research into personalized risk assessment and safer contraceptive alternatives is warranted.