What Is Thrombophilia?

Medically Reviewed by Jennifer Robinson, MD on March 23, 2024
3 min read

If you cut your finger or bruise your leg, your body acts to stop the bleeding. Blood cells called platelets and blood proteins called clotting factors work together to form a clot. Once the bleeding stops, the clot dissolves.

But some people may have a condition called thrombophilia that makes them prone to getting blood clots even without an injury. This is also called hypercoagulability. It can happen if your body makes too much clotting protein. It also can happen if you don’t make enough proteins whose job is to stop the clotting process. In some cases, proteins in the clot may not dissolve even after they’re no longer needed. In other cases, your body makes proteins that damage blood vessel walls.

Thrombophilia can block blood vessels and cut off oxygen to your tissues or organs. It may lead to conditions like deep vein thrombosis (DVT), a blood clot in your leg, and a pulmonary embolism (a blood clot in your lungs). It also can give you a heart attack or a stroke.

There are two main types of thrombophilia:

Inherited thrombophilia. This means you were born with the condition. One or both of your parents passed on a faulty gene or genes.

Inherited thrombophilia comes in several forms. The most common are factor V Leiden mutation, which 1 in 20 people of European descent have, and the prothrombin G20210A gene mutation or factor II mutation, which happens in 2% of the population.

Acquired thrombophilia. This is when your liver, kidney, or another organ doesn’t make or clear away clotting proteins as it should. It often happens after bed rest following a surgery or because of a major illness like cancer. Antiphospholipid antibody syndrome is the most common acquired thrombophilia. It is an autoimmune disorder that may raise your chances of having pregnancy complications and miscarriage.

You may not know you have thrombophilia until you get an abnormal blood clot. But that may not happen very often. Signs that you have the condition include if you get an unexpected DVT or have blood clot problems in an unusual part of your body, especially if you’re young and don’t have any obvious health issues.

If you have an autoimmune condition like lupus, it may make you more likely to have acquired thrombophilia.

Thrombophilia isn’t the only reason for clots to form. Others include:


Your doctor can check for thrombophilia with blood tests. They look for abnormal genes and specific antibodies. They measure levels of clotting proteins in your blood.

Your doctor may recommend testing in order to decide on your treatment choices, such as what type of blood thinner and how long you should take it. A test also may help answer how likely you are to get more blood clots, and if your family members also may have thrombophilia.

A genetic counselor may help you understand what the test results mean for you and your loved ones.

There is no treatment for thrombophilia until you get a blood clot. What happens then depends on where the clot is, its size, and other things.

If you have the antiphospholipid antibody syndrome form of thrombophilia, you may need long-term treatment with blood thinners.

If you’re a woman, you may need to avoid certain forms of hormonal birth control that have estrogen. You could take progestin-only pills instead. Your doctor also may recommend staying away from hormone replacement therapy for menopause symptoms.

If you have thrombophilia, you can lower your chances of having unwanted blood clots with lifestyle changes, including: