Clots can limit the flow of blood in the veins causing pain and swelling. If the clot dislodges there is a danger of it travelling to the lungs blocking the blood supply there (pulmonary embolism) and causing breathing problems.

Not all blood clots cause DVT as your body usually absorbs them gradually.

What causes DVT?

DVT can occur for no reason. However there is more risk of developing DVT if:

  • you smoke
  • you are immobile (especially if you have had an operation on your hips or knees)
  • you are travelling long distances (long haul flights)
  • you have had DVT previously
  • you have a family history of DVT
  • you are very overweight
  • you have a long term illness such as cancer, heart disease, inflammatory bowel disease or kidney disease
  • you have a condition that means your blood clots quickly
  • you are using contraception that contains oestrogen or hormone replacement therapy
  • you are pregnant or have recently given birth

Signs and symptoms of a DVT to look out for:

  • Swelling
  • Pain or tenderness, difficulty bearing full weight on affected leg
  • Increased warmth in the swelling
  • Red or discoloured skin
  • Mild fever

These symptoms can be a sign of other problems. Contact your GP or surgeon if you are at all concerned.

How can I prevent DVT?

In some cases your GP or surgeon may prescribe medication to prevent your blood from clotting. This is common practice following major surgery of the lower limbs. 

You may be advised to wear compression stockings to reduce pain and swelling in your legs. 

Following major surgery you may have leggings and an air pump on your legs to keep the blood flowing through your legs. Painless pressure is provided intermittently preventing blood from standing in any area during early recovery.

If you are travelling you should try to remain active, moving around as frequently as possible. While seated you should exercise the muscles in your lower body to keep the blood flowing freely. Wear compression stockings (sometimes called travel socks) for any journeys over four hours. 

Worried about DVT? Speak to your GP or surgeon.