What Are the Causes of Urinary Infections?

Sexual Intercourse

A urinary tract infection--often called a UTI--occurs when bacteria infect the urinary tract, and the resulting infection in the bladder may travel to the kidneys, says the Mayo Clinic. Most of the time, UTIs strike women, infecting the urethra and the bladder. One of the most common causes is having sexual intercourse--although, says the Mayo Clinic, women can get a urinary tract infection without having intercourse. An infection called cystitis, which affects the bladder, can occur because of E. coli bacteria that lives in the gastrointestinal system.

Female Anatomy

If the urethra becomes infected, the condition is known as urethritis. Bacteria from the gastrointestinal system--specifically the anus--infect the urethra. Because the urethra is so close to the anus in women, these bacteria can commonly infect the urethra. The bladder is also easily infected because the opening of the urethra is so near the bladder.

Hygiene and Urination

The germs from the anus can easily spread to the vagina if you wipe from the anus to the vagina after a bowel movement, says the National Women's Health Information Center. Always wipe from front to back to keep germs out of the urethra. It's also important to urinate frequently--whenever you feel the urge. Holding in urine can allow bacteria to form, causing a urinary tract infection. Birth control methods may also contribute to a UTI, such as using a diaphragm or condom, which can trap bacteria. Use of a catheter--a tube inserted in the urethra to allow urination, perhaps during surgery or a medical procedure--can also cause a UTI.

Risk Factors

Being diabetic or post-menopausal, lacking adequate estrogen, can increase the likelihood of developing a urinary tract infection. Diabetes makes the body more vulnerable to infection, and insufficient estrogen changes the chemical and bacterial balance of the vagina, says the NWHIC. Being pregnant, insufficient water intake, having kidney stones and anatomical abnormalities of the urethra can also increase the risk of developing a UTI, says the U.S. National Library of Medicine.