Factors that increase a child's risk of urinary tract infection (UTI) include:

• Abnormalities of the urinary tract, including kidney stones and other urinary obstructions. Structural or functional problems that limit the kidneys' or the bladder's ability to eliminate urine properly can increase the risk of UTIs. These problems may be present at birth or may develop soon after.
• Infrequent urination, incomplete emptying of the bladder, or constipation. These patterns are common during toilet training and make it easier for bacteria to build up in the urine.
• An uncircumcised penis. The foreskin can trap bacteria, which can then enter the urinary tract and cause infection.
• Catheterization, which is used in a hospital when a child is unable to urinate on his or her own. Bacteria can enter the catheter and start an infection.
• Previous UTIs. The risk for future infections increases with each additional infection.
• History of UTI or the backward flow of urine from the bladder into the kidneys (vesicoureteral reflux) in a parent or sibling.

Infants and young children who develop UTIs often have vesicoureteral reflux (VUR). In most cases it does not raise a child's risk of UTIs, but it could raise the risk of kidney damage caused by infection.