Blood flow in healthy leg veins allow blood to flow against gravity back to the heart. The tiny valves in the veins open and close to help control blood flow and pressure. Venous stresses such as pregnancy or standing for long periods of time can weaken and stretch the veins in the leg. The weakening can create obstructions in blood flow allowing blood to pool in the legs. This impairment, also called “reflux” can cause veins to distort, lose their form and protrude from under the skin. The protrusions present as unsightly varicose veins.