Understanding the Ten Common Causes of Blood Clots

3. Oral Contraception

Increased amounts of the hormone estrogen are among the biggest risk factors for blood clots. Oral contraceptives, also known as birth control pills, contain estrogen and other hormones that increase the risk of clotting. This risk is much higher for smokers than for regular users of birth control pills, as well as for those with a family history of blood-clotting issues. Many newer oral contraceptives, such as the mini-pill, only include progestin to reduce the chances of a clotting problem. However, it is still critical to avoid smoking while using oral contraceptives to keep this risk as low as possible.