bladder infections are more common in some families. other risk factors include diabetes, being circumcised, and having a large prostate (a gland around the urethra in males). complicating factors are not completely clear. these factors may include some anatomic problems (relating to physical narrowing), functional, or metabolic problems. a complicated uti is more difficult to treat and usually needs more aggressive evaluation, treatment, and follow-up. in children, utis are linked to vesicoureteral reflux (an abnormal movement of urine from the bladder into ureters or kidneys) and constipation.