The reality: By the end of pregnancy, your legs may look like a highly detailed roadmap of Minnesota. If you see big, blue, bulging veins (they'll look like rivers) on your legs, you probably have varicose veins. If you see little clusters of red, blue, or purple veins (these look more like secondary roads) that linger close to the surface of the thighs, calves, knees, and ankles, you have a case of spider veins. All told, both are pretty common phenomena. "Twenty percent of pregnant women develop varicose veins and 80 percent develop spider veins," says Luis Navarro, MD, director of the Vein Treatment Center, in New York City.
The reason: While the exact cause of vein problems is unknown, pregnancy is the biggest single accelerating factor. A pregnant woman has 20 percent more blood in her circulatory system to nourish her growing child; since 70 percent of circulating blood is stored in the venous system, this extra blood ups the amount of pressure applied to vein walls, which can cause them to bulge and darken. Plus, the growing uterus puts pressure on pelvic veins, which slows the flow of blood from the legs to the heart. This can damage the tiny valves that help direct blood flow in the veins, causing spider veins. Pregnancy hormones don't help either; they cause blood vessels to dilate, which also increases vein pressure and makes the whole road map worse. (And if your mom had them, you might too.)
The relief: Fortunately, unsightly vein problems are treatable, but that largely depends on the extent and severity of the condition. Options include wearing support stockings with compression; sclerotherapy, which involves injecting veins with a solution that causes them to collapse and reabsorb into the body; and laser therapy, which seals in the vein.