The valves of a normal and healthy vein work to keep your blood pumping in a single direction, running from the feet up toward the heart and lungs. Due to certain factors like genetics, pregnancy, or weight gain these valves can become damaged and results in bi-directional, or backflow of blood. This causes your blood vessels to expand from increased pressure and varicose veins are formed. These bulky and protruding veins most typically appear on the legs, and are common in both men and women. Luckily, there are many options when it comes to dealing with this type of condition, and medical advancements are continuously made, creating treatments that yield better results with less of a risk.