What causes varicose and spider veins?

Heredity: Far and away, the major cause of varicose and spider veins is heredity. Other factors can contribute to their development if you have inherited a tendency to get varicose veins in the first place. These include prolonged standing, age, pregnancy, hormones, and trauma. Surprisingly, obesity has not been shown to be a cause of varicose veins. It does increase the risk of complications though.

Many factors.: Varicose veins are usually due to leaking(refluxing) vein valves. Spider veins could be due to this as well but hereditary plays a key role. Factors that would increase your risk of developing either type of vein would be pregnancies in females and the greater the number, the greater the risk, hereditary, increasing age, hormones, standing or sitting in place and sometimes localized trauma.

Genetics & Leg Veins: Spider veins & varicose veins are typically inherited as a genetic familial condition. Underlying vein valve weakness & vein wall abnormalities are to blame. Others factors that can accelerate the process are pregnancies, prolonged standing occupations, & trauma. Female gender & increased aging also have increased incidence. Varicose veins are more serious & should be assessed by vascular surgeon.