Varicose veins occur when veins just below the skin's surface are damaged, become swollen and fill with too much blood.
Veins are the blood vessels that return blood to the heart. Arteries carry blood away from the heart to the rest of the body,
Varicose veins most commonly occur in the legs. In about 50% of cases, the condition runs in families, and probably is related to an inherited weakness in the veins' walls or the valves inside veins that keep blood from backing up.
Pregnancy is another common cause of varicose veins. During pregnancy, the volume of blood increases causing veins to expand. Also, occupations that require uninterrupted standing (waitresses and waiters, nurses, mothers with young children) may force leg veins and valves to work against gravity for hours, increasing the risk of pressure-related vein and valve damage. Garters also can increase the risk of varicose veins if their tight elastics slow blood flow in the legs.
Varicose veins are 2 to 3 times more common in women than men. Obese people are more likely to develop varicose veins.
Varicose veins can be associated with prior blood clots and damage to the deeper veins in one or both legs, a situation that sometimes can lead to chronic venous insufficiency. When this happens, the veins lose their ability to effectively move blood back to the heart. This can cause significant leg swelling and skin sores or ulcers.