What Causes Blood Clots in Lungs (and Increases Your Risk)
Medically reviewed by Reza Samad, MD
A blood clot in the lungs (pulmonary embolism) occurs when a mass of blood (clot) suddenly blocks one of your pulmonary arteries that send blood to the lungs. A blood clot in the lungs can be life-threatening and is often caused by deep vein thrombosis (DVT). A DVT is a clot that occurs in some of the deeper veins in the legs and moves through the body. Other causes of blood clots in the lungs are a long period of inactivity and having surgery.
This article looks closer at the causes, risk factors, and prevention of blood clots in the lungs.
Three Things That Cause Blood Clots in Lungs
Clotting is a normal bodily function that helps with healing. But when blood clots occur in your veins or lungs, they can inhibit blood flow and lead to severe problems. Below are the three most common causes of blood clots in your lungs.
Deep Vein Thrombosis
Deep vein thrombosis is the formation of a clot in the deep veins of the legs. This is the most common cause of blood clots in the lungs. However, blood clots in the lungs also can occur from DVT in the upper body, such as in the arms.
Surgery
The risk for blood clots in the lungs increases after surgery for several reasons. First, a longer surgery means that the blood in your body is more stagnant, leading to less blood flow and an increased chance of a blood clot that is able to form. Surgery also can lead to the release of other material in the bloodstream that could form a clot, such as fat, an air bubble, or amniotic fluid.
Long Periods of Inactivity
Extended periods when the body isn't moving, such as during a long flight, a lengthy surgery, or long-term bed rest, may increase the risk of blood clots in the lungs.
What Increases the Risk of Getting Lung Blood Clots?
In addition to the causes above, the following conditions or circumstances can increase your risk of getting a lung blood clot:
Severe injury or fracture
Stroke
Cancer
Childbirth and pregnancy
Family history or health history of clotting disorders
Long periods of inactivity
Smoking
Using birth control pills or estrogen therapy long term
Obesity
The risk for a blood clot that's not just in the lungs is 5 times greater during pregnancy than at other times. Having a cesarean section (C-section) doubles the risk of a blood clot.
Survival After Blood Clots in the Lungs
Many people survive and fully recover from blood clots in the lungs. Yet survival depends on the size and severity of the blood clot and other health factors. A study that looked at death from lung blood clots based on severity found that fewer than 2% of people with a low-risk lung blood clot died. However, 15.1% of people in the study with a submassive (less than the category of massive) lung blood clot passed within 90 days.
Related: Symptoms of Pulmonary Embolism
Minimizing Lung Blood Clot Risk After Surgery or Delivery
The risk of a lung blood clot is higher after surgery or childbirth (vaginal and C-section delivery). However, you can do some things, including the following, to minimize your risk of developing a lung blood clot if you are going to have surgery, while you're pregnant, or during childbirth:
Review your family history: Let your surgeon (or obstetrician-gynecologist (ob-gyn) if pregnant) know if you or someone in your immediate family has a history of blood clots.
Maintain a healthy weight: A body mass index (BMI) of more than 30 can increase your risk for blood clots. The risk is notably higher for those with a BMI over 40.
Stay active: Regular physical activity can promote better circulation. Always check with your provider what types of physical activity are OK for you.
Stay hydrated: The Centers for Disease Control and Prevention (CDC) recommends 10 glasses of water or other hydrating drinks while pregnant and 12 to 13 glasses daily while breastfeeding.
Consider medications: Talk to your healthcare provider about blood thinners, which can lower the risk of blood clots. You may need to use medicines that reduce the risk of blood clots during your full recovery time, which could be several months.
More Suggestions to Prevent Lung Blood Clots
Even if you aren't having surgery, you can do the following to reduce your risk of lung blood clots:
Get up and walk around periodically when traveling: If you're in a car, this could mean getting out to stretch and walk around every couple of hours. On a plane, walk around when possible. Rotate your ankles and lift your knees regularly to encourage blood circulation.
Wear compression socks: They help with blood flow in your legs and can decrease discomfort.
Stay hydrated: Being dehydrated can increase your risk of developing a blood clot.
Reassess hormone medications: Hormone therapy and oral contraceptives can increase the risk of a blood clot in the lungs. Your healthcare provider can help determine whether hormone supplements are suitable for your health needs or discuss alternatives.
Quit smoking: There are resources to help you quit if you do smoke.
Uncontrollable Risk Factors for Blood Clots
Although you can do some things to reduce your risk for blood clots in the lungs, there are some uncontrollable factors. These include:
Blood clots that occur from a tumor
A family history of blood clotting disorders
Genetics that increase blood clot formation
Aging, as your risk for blood clots increases after age 40
Summary
A blood clot in the lung is often caused by DVT, or a blood clot that forms deep in the veins of the legs and then travels to the lungs. Childbirth, surgery, and long periods of inactivity all increase the risk for a blood clot.
You can take action to minimize your risk of getting a blood clot in the lung, such as moving around regularly, staying hydrated, and quitting smoking. If you will have surgery, talk to your provider about the use of blood thinning medication.
Read the original article on Verywell Health.
