Blood clotting is a natural process which helps stop bleeding. Movement of the leg muscles helps to squeeze blood through the deep leg veins back to the heart helping to maintain normal blood flow.
If blood begins to flow slower than normal through the veins it can start to clot. This is more likely to occur during periods of reduced mobility such as during or after surgery. The risk of these clots forming is also increased after major surgery when the blood thickens in an attempt to stop blood loss and heal blood vessels damaged during surgery.
While everyone will not get a blood clot, some types of VTE may be serious, so it is really important to try to prevent these clots in the first place.