The cause of varicose veins relates strongly to genetic predisposition which is why numerous members of the same family may experience vein problems. The severity of these problems may, however, vary between individuals. Standing for long periods can be a factor that exacerbates vein problems and is particularly problematic in those whose work requires them to stand for prolonged periods. Pregnancy is a major contributing factor for problem veins in many women. This can be due to a number of factors such as increased circulation and elevated pressure in the pelvic region late in pregnancy that creates pressure in leg veins. There is an increase in the hormone oestrogen which can cause new blood vessels to form as well as weaken the walls of existing blood vessels. Being overweight can worsen venous disease and can lead to an increased risk of recurrence after vein treatments. Trauma or injury to the legs can lead to varicose veins.