Mild congenital ureteral stenosis is not very serious; moderate to severe congenital ureteral stenosis is more serious and may cause some serious complications. Mild congenital ureteral stenosis may have no obvious clinical symptoms and will not cause too much impact, but you should see your doctor regularly for review and to understand the development of your condition. Moderate to severe congenital ureteral stenosis may be more serious and may cause hydronephrosis, which is manifested by waist soreness and pain, and may also easily induce pyelonephritis and other urinary tract infections, which may lead to chronic renal insufficiency as well as uremia in severe cases. Therefore, when congenital ureteral stenosis causes some obvious clinical symptoms, it is recommended to consult a doctor as soon as possible for examination and treatment to avoid adverse effects.