Congenital valve defects: Some individuals are born with blood valves that do not function effectively. These valves could enable blood to pool or back again up in to the legs, leading to varicose veins. From Mayo Clinic for your inbox Sign up for free and remain updated on analysis breakthroughs, https://www.sgvascularctr.com/varicose-vein-treatment-in-singapore-a-comprehensive-guide/