The most common cause of UTIs is bacteria from the bowel that live on the skin near the rectum or in the vagina, which can spread and enter the urinary tract through the urethra. Once these bacteria enter the urethra, they travel upward, causing infection in the bladder and sometimes other parts of the urinary tract.

Another cause of bladder infections or UTI is waiting too long to urinate. The bladder is a muscle that stretches to hold urine and contracts when the urine is released. Waiting too long past the time you first feel the need to urinate can cause the bladder to stretch beyond its capacity. Over time, this can weaken the bladder muscle. When the bladder is weakened, it may not empty completely and some urine is left in the bladder. This may increase the risk of urinary tract infections or bladder infections.

Other factors which may increase a woman's risk of developing UTI include pregnancy, history of urinary tract infections or bladder infections as a child, menopause and diabetes.