Varicose veins look like swollen veins raised above the surface of the skin, but they are actually just below the skin. They can be twisted or bulging and are dark purple or blue in color. They are found most often on the backs of the calves or on the inside of the leg. They are also commonly found in the anus, an less commonly in the vulva.
During pregnancy blood volume increases greatly and the weight of your developing baby and growing uterus puts extra pressure on your veins. This can cause veins to enlarge. Plus, pressure on the large veins behind the uterus causes the blood to slow in its return to the heart. Pregnancy hormones also relax the vein walls, allowing them to expand more easily. For these reasons, varicose veins in the legs and anus (hemorrhoids) are more common in pregnancy.