Deep Vein Thrombosis: What Causes It?

DVT is a potentially serious or even fatal vein condition. It occurs when platelets and plasma within blood do not mix and circulate properly. This slows down blood flow and causes a clot in a deep vein, preventing blood from returning to the heart. 

Deep vein thrombosis treatment is generally available for those who have the condition, but many can have the disease and not know it. Certain risk factors increase the chances of developing this disease. For example, pregnant women or those taking contraceptive medication are at a greater risk of developing blood clots. If someone has other chronic diseases such as heart disease or cancer, they are also at risk. 

Sometimes referred to as “economy class syndrome,” DVT is a potentially severe and usually silent disease related to long periods of immobility. It can affect younger as well as older individuals. 

Deep Vein Thrombosis

Common causes of DVT

Anything that interferes with blood circulation can cause DVT. Certain diseases such as inflammatory bowel disease and some cancers increase the risk of developing this disease. Following are some other causes to consider: 

  • Immobility

Immobility is one of the main reasons for developing DVT. When you are active, your leg muscles help maintain constant blood flow. However, when you sit or stand for a long time, blood can slow or stagnate, which leads to clots. This is why people in hospitals who cannot walk and those who drive or fly for long periods commonly end up with the condition. 

  • Pregnancy and postpartum

Although DVT during pregnancy is fairly rare, increased pressure in the pelvic area and veins in the legs can cause blood clots. Postpartum deep vein thrombosis can also be caused by damage to the blood vessels in the uterus and pelvic area after delivery. 

Women are five times more likely to form blood clots during pregnancy. Blood clots can occur at any time during pregnancy and the first six weeks after delivery. People with more severe varicose vein symptoms are more susceptible to DVT.

The American College of Obstetricians and Gynecologists (ACOG) also noted that the following pregnant women are more likely to develop DVT: 

  • Those with a family history of DVT
  • Those who are placed on bed rest during pregnancy
  • Those whose deliveries are performed by cesarean section
  • Use of contraceptives

Studies have shown that women who take combined hormonal contraceptives (estrogen and progesterone) have a higher chance of developing DVT. Contraceptives include birth control pills, patches, and rings, although the pill form is less risky than the other types. 

It should be noted that the overall risk is relatively low. For every 100,000 women aged 15 to 44 who use birth control, about 5 to 10 may develop a blood clot in a given year. 

The risk of blood clots when taking birth control pills is approximately doubled compared to those not on birth control. With the use of patches, vaginal rings, or birth control pills containing desogestrel and drospirenone, the risk is about four times higher. If you have a family history of blood clots and want to take birth control pills, discuss your risk level with your doctor. Alternative contraceptive methods may be available, such as contraceptive pills with progesterone only, or non-hormonal intrauterine devices (IUD). 

  • Injury

When the body is injured by a surgical incision (whether accidentally or deliberately), proteins in the blood will collect at the wound site to form a blood clot. This is usually healthy and prevents excessive bleeding. However, the same process can also form a deadly DVT. 

  • Genetics

If you have an inherited blood clot disease, your risk of DVT is increased. Hereditary thrombosis, for example, is caused by specific genetic mutations that increase the risk of abnormal blood clots. The tendency to thrombosis itself can cause DVT or aggravate the risks associated with the above factors.

Suppose you or your family have had DVT or a pulmonary embolism (PE). In that case, you may have inherited a similar problem with blood clotting that can lead to disease. It can also lead to heart attack, stroke, or even miscarriages. If you think you may have an inherited blood clot disease, discuss with your doctor whether to get tested. 

According to the National Institute of Health, approximately 50% of people with hereditary antithrombin deficiency will form one or more clots during their lifetime.

Lifestyle risk factors

DVT can happen to anyone, but certain lifestyle habits increase the risk of the disease. The following are considered modifiable risk factors: 

  • Inactivity
  • Being overweight or obese
  • Smoking

If you have a history of DVT or your legs are often swollen, contact an experienced medical professional. You may need Philadelphia vein treatment as soon as possible. It’s important to get DVT treated early to stay healthy and avoid a clot that could become fatal.




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