The Top Blood Clot Risk Factors

Emily Lockhart

Published on November 25, 2015 Updated on August 20, 2020

Health Check Certified By: Dr. Gerald Morris

Blood clots, or what’s medically referred to as deep vein thrombosis (DVT), are blood clots that tend to form and block blood flow deep in veins in the pelvis, lower leg, thigh, or other areas of the body. According to research from the Cleveland Clinic, a DVT can become fatal if it dislodges and travels through the bloodstream to block a blood vessel in the lung, causing a life-threatening pulmonary embolism (PE).

The best way to prevent a blood clot is to know and avoid the risks associated with the development of DVT development. Seven of the top blood clot risk factors are…

1. Long Periods of Immobility

According to research from the American College of Phlebology, one of the most ideal environments for the formation of a DVT is a long stretch of sitting or immobility where muscles don’t contract.

Think about the times you sat for long periods without moving—such as on a long airplane trip, bus ride, or car trip. This immobility can drastically decrease blood flow and lead to blood clot formation. Long periods of stasis (i.e., following a surgery or injury) are also considered risky for DVT formation.

2. Age and Body Weight

Being overweight can contribute to numerous health issues, including the formation of a blood clot. Health experts at the Mayo Clinic point out that carrying around excess body weight increases the pressure in the veins in your pelvis and legs.

The Clinic also notes that individuals over the age of 60 are at greater risk for DVT. However, blood clots and DVTs can form at any age, particularly if a number of risk factors are present.

3. Pregnancy

When we’re pregnant we’re suddenly carrying around a lot of extra weight—particularly in the final trimester. The American Pregnancy Association notes that this excess pressure can increase the stress and compression on the veins in an expecting woman’s pelvis and legs.

In addition, the risk of developing a DVT or blood clot can last up to 6-weeks after a woman gives birth. This is especially true for mom’s who are inactive after birth (i.e., if they’re recovering from a Caesarian section [C-section]).

4. Injuries or Surgeries

The folks at the Mayo Clinic find that prolonged bed rest can lead to the development of DVT following an injury or surgery.

Any prolonged period of inactivity—such as a hospital stay—can lead to decreased contraction of the leg muscles, decreased blood circulation, and higher risk for a blood clot. Patients with paralysis are also at high risk for DVT.

5. Genetic Predisposition

If you have a genetic or family history of DVT, consider yourself at risk for a blood clot. Research from the American Heart Association states that a family history of DVT and PE are both prime risk factors for developing DVT.

In a 2011 study conducted by the Thrombosis and Atherosclerosis Research Institute on 45,362 patients hospitalized for DVT, a spike was found in DVT incidence rates in relation to genetic or familial clustering of this disorder.

6. Birth Control

The National Blood Clot Alliance (NBCA) notes that although birth control does not necessarily cause blood clots, some types of oral birth control medications can heighten a woman’s risk of DVT by approximately 40-percent.

The NBCA points out that both oral contraceptives and hormone replacement therapy (which contains estrogen and progesterone hormones) may intensify blood clotting factors—leaving women at risk of developing DVT.

7. Smoking

If you smoke, you already know that you’re not doing your health any favors. According to research from the American Thoracic Society, smoking impacts both blood circulation and the blood’s ability to clot—raising the risk of DVT.

However, deaths from DVT and PE are elevated in patients with chronic obstructive pulmonary disease (COPD) due to a combination of factors—namely blood coagulation abnormalities and reduced mobility.

Emily Lockhart

Emily Lockhart is a certified yoga instructor and personal trainer. She believes that being healthy is a lifestyle choice, not a punishment or temporary fix to attain a desired fitness or body image goal. Anna helps her clients take responsibility for their own health and wellness through her classes and articles on ActiveBeat.