If you're concerned that your baby may have a urinary tract infection, or bladder infection, here are some basic facts that might help. The urinary tract makes, transports, stores, and ultimately expels urine. There are four distinct parts to the urinary tract: the kidneys (which are the organs that make urine), the ureters (which are the tubes that carry urine from the kidneys to the bladder), the bladder (where urine is stored until the body is ready to expel it), and the urethra (which is the tube that carries urine out of the body from the bladder). When bacteria get into urine, they can create inflammation and infection in any of these places. This type of infection is known as a urinary tract infection, or UTI. Different terms are sometimes used to refer to these infections, depending on where the symptoms occur. For example, when something is called a bladder infection, it usually is a UTI which has localized symptoms in the bladder. About 8% of girls and 2% of boys will have a UTI during their childhood. UTIs occur more frequently in girls because their urethra is a different shape and length than a boy's urethra, and because the opening where they expel their urine is closer to the rectum, a likely source of bacteria. Commonly, the bacteria is spread when the poop gets trapped in the folds of the vagina surrounding the urethra, and the bacteria work their way up the short urethra and into the urinary tract, causing a UTI. Girls in diapers are especially prone to such infections. The most common symptom of a UTI in a baby is fever with no other obvious symptoms. Other signs that your baby may have a urinary tract infection include crying or any other indication that urinating is painful, urine that is cloudy, bloody, or smells unusual, refusal to eat, or vomiting. Bladder infections, if left untreated, can quickly lead to kidney infections, and in severe cases, to bloodstream infections, in infants under six months of age. Fortunately, the treatment for UTIs is relatively straightforward - a liquid antibiotic, like amoxicillin, for simple infections without fever. However, if there is a fever, your child will likely require a few days of hospitalization for IV antibiotics. Remember that if your doctor does prescribe an antibiotic that your baby needs to take the full course, all the doses the doctor prescribes, even if she seems to be feeling better. UTIs are common in babies, and it's important to identify them early so that they can be treated effectively. If you are concerned that your baby might have one, call your pediatrician immediately!