Combined oral contraceptives increase the risk of venous thrombosis through multiple pathogenetic mechanisms, including altered clotting factors and endothelial activation.
What are the pathogenetic mechanisms of thrombosis development during combined oral contraceptive use?
Clinicians must carefully evaluate individual risk factors for thrombosis when prescribing combined oral contraceptives due to their multiple pro-thrombotic mechanisms.
Combined oral contraceptives (COCs) remain one of the most popular reversible contraceptive methods worldwide. Still, regardless of the drug composition and duration of therapy, almost all COCs are associated with the risk of venous thrombosis. This review highlights the main pathogenetic mechanisms of thrombosis development during oral contraceptive use. Increase the production of certain clotting factors; a decrease in antithrombin and protein S levels; acquired resistance to activated protein C; a reduction in tissue factor pathway inhibitor (TFPI); indirect endothelial activation; inhibition of endogenous fibrinolysis; regulation of tissue factor by estradiol-sensitive microRNA; homocysteine imbalance caused by decreased intestinal reabsorption of folates and vitamin B-12; reduced bioavailability of nitric oxide (NO) due to high homocysteine levels; higher blood pressure, water retention, insulin resistance, increased levels of pro-inflammatory C-reactive protein (CRP) and uric acid, and antifibrinolytic (plasminogen activator inhibitor 1 type, PAI-1) biomarkers as consequences of NO deficiency; increased platelet adhesiveness and ADP-induced aggregation, which promote fibrinogen binding; and increased expression of pro-inflammatory cytokines are the main thrombotic effects of COCs use. Clinicians should carefully evaluate each patient's individual risk factors when prescribing COCs and conduct regular monitoring to reduce the risk of complications.
Khizroeva et al. (Fri,) conducted a review in Venous thrombosis. Combined oral contraceptives was evaluated. Combined oral contraceptives increase the risk of venous thrombosis through multiple pathogenetic mechanisms, including altered clotting factors and endothelial activation.