Varicose veins are swollen, purple or blue, twisted veins in the legs. They are caused by hormone changes, obesity and pressure in the pelvic area. Most commonly found in women, pregnancy and heredity can also contribute to varicose vein formation.
Varicose veins occur when valves in the blood vessels stop functioning properly and are unable to transport blood from the extremities back up to the heart. As blood pools in the veins, they swell and thicken.