Deep vein thrombosis (DVT) is caused by a blood clot that forms in one or more of the deep veins in your body, typically in your legs. Clots can also occur in the arms.

DVT can be serious and is often underdiagnosed, according to the Centers for Disease Control and Prevention (CDC).The condition itself is not life-threatening, according to the Cleveland Clinic, but blood clots in the veins can break loose and move to the lungs, causing a potentially life-threatening pulmonary embolism.When this happens, the clot blocks blood flow to the lungs, which can be fatal, making it imperative to get prompt diagnosis and lifesaving treatment.

Fortunately, DVT is preventable and treatable if detected early.

Signs and Symptoms of DVT

If you have DVT, you may experience discomfort in your leg. However, the condition can occur without any symptoms.

According to the Mayo Clinic, signs of DVT can include:
  • Swelling in one leg (it’s rare that swelling would occur in both legs)
  • Pain in the affected leg
  • Skin that is red or discolored on the affected leg
  • Skin that is warm to the touch on the affected leg

If you see signs or symptoms of DVT, talk to your doctor. If you have symptoms of a pulmonary embolism, seek emergency medical assistance immediately.

According to the Mayo Clinic, signs of a pulmonary embolism include the following:
  • Unexplained or sudden shortness of breath
  • Chest pain or discomfort that worsens when you take a deep breath or cough
  • Dizziness or fainting
  • Rapid pulse
  • Coughing up blood

How Is DVT Diagnosed?

To check for DVT, your doctor will take a full medical history and perform a physical exam, including these common tests, according to the Mayo Clinic:
  • Duplex Venous Ultrasound This test shows the blood flow in your deep veins so your doctor can check for clots.
  • D-Dimer Blood Test This checks for elevated levels of the protein D-dimer (a sign of DVT).
  • Venography This X-ray of the veins in your legs and feet is another way to check for clots. It is rather invasive, so other tests are typically done first, so it is not often performed.
  • CT Scan or MRI These are often done to check for blood clots in the abdomen.

Treatment and Medication Options for DVT

According to the CDC, treatments for DVT include the following options:


Anticoagulants, or blood thinners, are usually the first-choice treatment for DVT. Although anticoagulants don't break up existing clots, they can prevent the clot from growing in size and prevent new clots from forming.

When you start anticoagulation therapy by injection, your doctor will often administer the first few doses, after which you may be able to administer the injections on your own.

Injectable blood thinners include these examples:

  • Lovenox (enoxaparin)
  • Fragmin (dalteparin)
  • Aritxtra (fondaparinux)
  • Heparin

If your doctor prescribes oral anticoagulation therapy — such as Coumadin (warfarin), Xarelto (rivaroxaban), Eliquis (apixaban), or Savaysa (exoxaban) — you will typically take these medications for three months or longer.

Your doctor may recommend regular blood tests to check how long it takes for your blood to clot. All blood thinners must be taken as prescribed to avoid serious side effects.


Also known as tissue plasminogen activators, thrombolytics are given intravenously (by IV) or through a catheter positioned near an existing blood clot. They are designed to break up clots.

Thrombolytics can cause serious bleeding. They are used only in life-threatening situations and only if you are hospitalized.


If you are unable to take blood thinners for any reason, your doctor may recommend a minor surgical procedure in which a filter is inserted into a large vein in your abdomen, known as the inferior vena cava.

This filter is designed to prevent any clots that break loose from traveling to your lungs.

Surgery and Socks

In rare cases, clots may need to be removed by surgery.

Finally, wearing compression stockings on your legs can help prevent swelling associated with DVT. The pressure they create lowers the risk of blood pooling and clotting.

Complications of DVT

Pulmonary embolism is the most dangerous complication associated with DVT, according to the CDC.

A pulmonary embolism occurs when a blood vessel in your lung is blocked by a blood clot that has moved from another part of your body, usually a deep vein in your leg. It can be fatal if left untreated.

Post-thrombotic syndrome (PTS) is another common complication associated with DVT. It's caused by damage to your veins from a blood clot that reduces blood flow in the affected areas. According to the CDC, one-third to one-half of people with DVT will develop PTS.

Signs and symptoms of PTS include:

  • Swelling or pain in your legs
  • Skin discoloration
  • Skin sores

Related Conditions and Causes of DVT

Being overweight or obese greatly increases the risk of DVT. According to the American Heart Association, people who are obese have twice the risk of blood clots than those who are a healthy weight.
Pregnancy also increases the risk of DVT. According to the CDC, pregnant women are 5 times more likely to get a blood clot than women who are not pregnant.The risk remains during pregnancy, through childbirth, and up to three months after delivery.
Pregnancy increases the risk of DVT for a number of reasons. A woman’s blood clots more easily during pregnancy to prevent excess blood loss during labor and for a period of time after delivery, according to the CDC.Later in pregnancy, the extra weight from the growing baby puts pressure on the pelvis and can decrease blood flow to the legs. Finally, pregnant women may have limited mobility during pregnancy and after delivery, which can increase the risk of blood clots.

DVT and COVID-19

Much attention has been paid to the risk of blood clots and the COVID-19 vaccine, but research suggests that the risk is much higher from the virus itself.

A study published in the The BMJ looked at the incidence of blood clots and stroke in people vaccinated with the AstraZeneca or Pfizer vaccines.

The results showed that for every 10 million people vaccinated with the AstraZeneca shot, 66 experienced a blood clot in their veins. This is compared with 12,614 per 10 million people with COVID-19.

The study also found that 143 people out of 10 million had an ischemic stroke in the 28 days after the first dose of the Pfizer vaccine, compared with 1,699 with COVID-19.

The research adds to the evidence that getting infected with COVID-19 is more serious than the potential side effect from the vaccine that protects against getting COVID-19.

Editorial Sources and Fact-Checking

  • What Is Venous Thromboembolism? Centers for Disease Control and Prevention. February 7, 2020.
  • Deep Vein Thrombosis (DVT). Cleveland Clinic. July 18, 2019.
  • Deep Vein Thrombosis (DVT): Symptoms and Causes. Mayo Clinic. December 22, 2020.
  • Deep Vein Thrombosis. American Academy of Family Physicians. September 10, 2020.
  • Treating and Managing Pulmonary Embolism. American Lung Association. October 23, 2020.
  • Diagnosis and Treatment of Venous Thromboembolism. Centers for Disease Control and Prevention. February 7, 2020.
  • Prevent Blood Clots. Centers for Disease Control and Prevention. October 13, 2020.
  • Data and Statistics on Venous Thromboembolism. Centers for Disease Control and Prevention. February 7, 2020.
  • Risk Factors for Venous Thromboembolism (VTE). American Heart Association. March 30, 2017.
  • Pregnant? Don’t Overlook Blood Clots. Centers for Disease Control and Prevention. February 7, 2020.
  • Hippisley-Cox J, Patone M, Mei X, et al. Risk of Thrombocytopenia and Thromboembolism After COVID-19 Vaccination and SARS-CoV-2 Positive Testing: Self-Controlled Case Series Study. The BMJ. August 27, 2021.


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