You are in Parenting and Pregnancy . To circulate oxygen-rich blood from the lungs to all parts of the body, your arteries have thick layers of muscle or elastic tissue. To push blood back to your heart, your veins rely mainly on surrounding muscles and a network of one-way valves. As blood flows through a vein, the cup-like valves alternately open to allow blood through, then close to prevent backflow.
Varicosity results from a chronic increase in blood pressure, which dilates the vein.
Instead of flowing from one valve to the next, the blood begins to pool in the vein, increasing venous pressure and the likelihood of congestion while causing the vein to bulge and twist. Because superficial veins have less muscular support than deep veins, they are more likely to become varicose. Any condition that puts excessive pressure on the legs or abdomen can lead to varicosity. The most common pressure inducers are pregnancy, obesity and standing for long periods. Being sedentary likewise may contribute to varicosity, because muscles that are out of condition offer poor blood-pumping action.