Know Your Clot Risk

Being aware of risk factors, and especially of your own risk factors is really important in helping you to avoid and protect yourself from thrombosis.

A venous thromboembolism (VTE), often referred to as a deep vein thrombosis (DVT), pulmonary embolism (PE), thrombosis or blood clot, is a clot that forms in a vein.

It is important that you discuss this with your doctor
if you have any risk factors.

The most common risk factors for thrombosis are:

Recent hospitalisation for illness or surgery (up to 90 days post discharge).
Previous history of thrombosis.
Recent major surgery, particularly of the pelvis, abdomen, hip, knee, (up to 90 days post discharge).
Severe trauma, such as a car accident.
Injury to a vein that may have been caused by a broken bone or severe muscle injury.
Cancer and cancer treatments.
Contraceptive pill for birth control in particular those that contain oestrogen, such as the pill, patch or ring.
Pregnancy, (including the six weeks after the baby is born).
Oral (tablet form) hormone therapy (HRT), which contains oral oestrogen.
A family history of blood clots.
Obesity.
Long-term bed rest.
Long periods of inactivity including sitting for long periods of time, especially with legs crossed.

Please select one of the following for more information

Hospital risk factors for blood clots

Around 50%-60% of blood clots are associated with being admitted into hospital. This can be due to becoming immobile for a period of time, treatments you received or undergoing procedures during your stay.

All hospitals are expected to complete a DVT risk assessment for every patient admitted into hospital – whether as a planned admission or following an urgent or acute admission. Risk assessing an individual is very simple and involves a healthcare professional reviewing a series of questions that help lo assess a patient’s risk level and if any therapies or actions need to be taken to reduce their risk.

If you are admitted into hospital, you should be Risk Assessed for Blood Clots

On admission to hospital.
Regularly during your stay in hospital as your level of risk may change.
Prior to discharge as you may need to carry on taking blood thinning drugs when you go home.

Your risk of developing a blood clot may increase if you are admitted into hospital as an emergency admission, a planned admission for a procedure, or if you are receiving treatment. It is helpful to talk with your health care professional about your VTE risk and what can be done to reduce.

Things to reduce the risk may include:

A VTE risk assessment carried out by a medical professional to identify if you are at risk of a blood clot.
Staying active and mobile if you are able, for example, making sure you go for short walks.
Ensure you stay well hydrated by drinking plenty of water while you are in hospital and after discharge.
Using any compression devices advised. These are usually inflation devices.
Taking an anticoagulant (sometimes called a ‘blood thinning’ medication) as advised. This may come in the form of oral tablets or injections.
Ask for any information resources the ward or department may have about blood clots.

Play Video

See hospital risk factors

Cancer related risk factors for blood clots

Having cancer and receiving certain treatments for cancer, might mean that you have a higher risk of developing a blood clot. This could be due to a number of things.

The type of cancer:

Cancer cells produce and release substances that stimulate the blood to make more clotting factors.

There are several known cancer types which increase the risk of developing a blood clot such as cancer of the:

Pancreas
Bowel
Lung
Stomach
Ovary
Womb
Cancers spread to local lymph nodes or other parts of the body

Cancer treatments:

Certain treatments can increase the risk of developing blood clots.

When chemotherapy kills cancer cells the cells can also release substances that cause more blood clotting

The hormone drug tamoxifen is also known to increase the risk of blood clots.

The newer immunotherapy treatment may also increase the risk of blood clots.

See cancer risk factors

Early Pregnancy Blood Clot Risk Assessment Questionnaire

The Early Pregnancy Blood Clot Risk Assessment Questionnaire is designed to identify women who are at increased risk of developing a blood clot (venous thromboembolism, or VTE) in early pregnancy, even before their first maternity booking appointment. It helps women and healthcare professionals recognise important risk factors that may require urgent review and preventative treatment. It is evidence based and the work of a large group of experts and patient representatives, working with NHS England.

See pregnancy risk factors

Pregnancy risk factors for blood clots

Being pregnant, and the six weeks after having a baby, can raise the risk of getting a blood clot (we call this “venous thromboembolism.”)

The risk starts to grow from the moment a baby is conceived. It gets highest around the time of birth and stays high for six weeks after.

While a woman is pregnant, her blood slowly becomes thicker and stickier. This is actually helpful — it stops her losing too much blood when the baby is born.

But it can also cause a problem. As the baby grows, it presses on blood vessels near the hips. This makes it harder for blood to flow back up from the legs. Slower blood flow, plus thicker blood, means a higher chance of clots forming

See pregnancy risk factors

Hormone therapies risk factors for blood clots

Hormone therapies can bring many benefits, however, some types of hormones and the way they may need to be taken can increase the risk of developing a blood clot.

The most common areas where hormone therapy and increased risk of blood clots will need to be considered are:

The combined oral contraceptive pill.
Hormone replacement therapy (HRT) to treat symptoms caused by menopause.
Hormones and thrombosis risk in transgender health.

See hormone therapies risk factors