Which factor increases the risk of thromboembolism when using combination oral contraceptives?

• A. Heavy smoking
• B. Regular exercise
• C. Diet high in fiber
• D. No history of thrombosis

Answer: (A)

Heavy smoking increases thromboembolism risk with combination oral contraceptives because estrogen in the pills promotes a procoagulant state, and smoking compounds that effect. Estrogen raises the liver’s production of clotting factors and decreases natural anticoagulants, nudging the blood toward clot formation. Smoking adds endothelial irritation, enhances platelet activation, and fosters a more prothrombotic environment through vasoconstriction and oxidative stress. Together, heavy smoking and estrogen-containing contraception markedly raise the chance of blood clots, including venous thromboembolism and related complications. The other options don’t add this risk in the same way: regular exercise tends to reduce thrombotic risk, a fiber-rich diet supports overall cardiovascular health, and having no history of thrombosis indicates lower baseline risk.