Urine normally flows in one direction -- down from the kidneys, through tubes called ureters, to the bladder. Vesicoureteral reflux (VUR) is the abnormal flow of urine from the bladder back into the ureters.
VUR is most commonly diagnosed in infancy and childhood after the patient has a urinary tract infection (UTI). About one-third of children with a UTI are found to have VUR. VUR can lead to infection because urine that remains in the child's urinary tract provides a place for bacteria to grow. But sometimes the infection itself is the cause of VUR.