They occur in otherwise healthy women and girls who have normal urinary tracts, normal urinary functioning, and no underlying physical problems. Pregnant women get about the same number of UTIs as nonpregnant sexually active women of childbearing age. However, when a pregnant women gets a UTI, it is more likely to travel upwards to the kidneys. Diabetics run a higher risk of UTIs because their immune systems are suppressed. Additionally, their urine has a higher glucose content, which is a good growing medium for any bacteria that enter the bladder.
Infection begins when bacteria stick to the opening of the urethra and multiply.
The closeness of the female urinary tract to these areas and the shorter length of the urethra make it more susceptible to infection. Using a diaphragm for contraception can be an additional risk factor for UTIs. The diaphragm may press on the neck of the bladder, preventing it from emptying completely and leaving a pool of stagnant urine for bacteria to grow in. Bacteria may also enter the urinary tract when the diaphragm is inserted and removed and when it is left in place longer than recommended. Not all UTIs are a result of sexual activity.