We all know what varicose veins look like-the hardened, bulging blue knots standing out in the legs which are caused, some people say, by heredity but which are likely to have been made for worse by neglect. The valves which control the flow of blood in veins and arteries collapse as a result of poor circulation which can be caused by carrying too much weight, especially during pregnancy. Standing for too many hours at a time is also a prime factor.