Your chance of getting a blood clot increases: • As you get older • If blood clots in blood vessels (veins or arteries) runs in the family • If you smoke, especially if you are over 35 years of age • If you stay in bed for many days • If you are very overweight • If you have just had a baby, miscarriage or abortion • If you have had a serious injury, particularly of the leg or hip • If you have had or are going to have a major operation or need to have bed rest for a long time.