For a patient with a smoking history and obesity, why should the use of oral contraceptives be avoided?

The use of oral contraceptives should be avoided in patients with a history of smoking, especially in those who are older or have additional risk factors such as obesity, because of the significant increased risk of thromboembolic events, including deep vein thrombosis (DVT) and pulmonary embolism (PE). Smoking alone is a well-established risk factor for vascular problems, and this risk is compounded by estrogen-containing contraceptives that can further increase the likelihood of blood clot formation.

Estrogen promotes blood clotting by increasing the levels of certain clotting factors and can decrease the activity of natural anticoagulants in the body. When combined with the effects of smoking, which can damage blood vessels and promote a pro-coagulative state, the overall risk of serious cardiovascular events becomes markedly higher. Therefore, careful consideration and discussion about contraceptive options are crucial for individuals with these risk factors to ensure their safety and well-being.