Top 6 Risk Factors for Pulmonary Embolism

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Pulmonary embolism (PE)--a blockage of the main artery of the lung or one of its branches by a substance that has traveled through the blood system from elsewhere in the body--occurs equally in men and women, but risk increases with age. For every 10 years after age 60, the risk of having PE doubles. Other than age, here are health and lifestyle factors that may put you at a greater risk.

Deep vein thrombosis (DVT)

Your risk for PE is high if you have deep vein thrombosis (DVT) or a history of DVT. In DVT, blood clots form in the deep veins of the body—most often in the legs. These clots can break free, travel through the bloodstream to the lungs, and block an artery.

Prolonged immobilization

If you're sitting on an airplane for an extended period of time, or are relegated to a bed after recovering from a surgery, your blood flow is at a point of stasis and could put you at risk for a PE. If you're known to have poor circulation, always speak with your doctor about preventative measures before a long trip or surgery.

Birth control pills

The birth control pill contains different forms of the female hormones estrogen and progestin. Estrogen increases the risk of DVTs by increasing the production of certain chemicals necessary for the blood to clot. It also increases platelet numbers and the stickiness of platelets, which increases clot formation. This same increase in estrogen also occurs naturally in late pregnancy, resulting in a similar or greater increase in the risk of PE.


Basic research studies have implicated smoking in various abnormalities of blood coagulation, which is how a clot is formed. Researchers are not sure whether it's the nicotine itself, or other effects of smoking that raise the risk of PE and DVT in smokers.

Genetic predisposition

Genetic predisposition, most commonly, Factor V Leiden deficiency, MHFTHR mutation, Protein C or Protein S deficiencies or anitithrobin III deficiency are all risk factors for PE.