• Health & Wellness

    Number of Factors May Contribute to Urinary Tract Infection in Women

Number of Factors May Contribute to Urinary Tract Infection in Women

April 19, 2013

Dear Mayo Clinic:

I am a 46-year-old woman and have never had a urinary tract infection before, but think I may have one now. Do I need to be seen by a physician for treatment? What causes UTIs?


Urinary tract infection, or UTI, is generally a bacterial infection that can affect any part of the urinary tract. Up to 50 percent of women encounter UTIs during their lifetimes. When treated promptly, a UTI is typically curable. Antibiotics typically play a key role in treatment. Rarely do UTIs progress to something more serious, such as an infection of the kidney or infection of the bloodstream. Because you have not previously been diagnosed with a UTI, you should make an appointment with your doctor to discuss your symptoms.

UTIs are typically caused by bacteria that live in the colon. The most common bacterium causing a UTI is a type of Escherichia coli (E. coli). The female anatomy increases risk of UTIs, because bacteria can easily migrate from the nearby rectum or vagina to the urethra and into the bladder.

Other factors also may contribute. Sexually active women are more prone to UTIs, and sexual activity is the leading cause of UTI. Changes associated with menopause may increase susceptibility to recurrent UTIs. The loss of estrogen results in thinning of the urethral tissue and disrupts the vagina's acidity level. When this happens, there can be a shift in the vagina's balance of "good" bacteria that normally disrupt the growth of unwanted bacteria, especially E. coli.

In addition, impaired bladder emptying, urinary incontinence, obstructed urine flow due to kidney stones in the urinary tract, diabetes or immunosuppression can increase the risk of UTIs. Placement of an indwelling urinary catheter is another factor that contributes to UTI occurrence.

The majority of UTIs — also referred to as cystitis or a bladder infection — affect the bladder and urethra (lower urinary tract). Classic signs and symptoms of urinary tract infections include the frequent urge to urinate (even if going only small amounts); a burning sensation or pain when urinating; abdominal pain or pressure; cloudy, dark or bloody urine; and/or foul-smelling urine.

Most UTIs are not serious. But if infection moves upstream and affects the kidneys, additional symptoms can occur. You may feel tired, shaky, weak or even faint. Other signs and symptoms of a kidney infection include fever or 101 degrees or greater, shaking and chills, upper back and side pain, and nausea or vomiting. A suspected kidney infection warrants immediate medical care to prevent bacteria from entering the bloodstream.

To confirm that you have a UTI, your doctor may check a sample of your urine for white blood cells, red blood cells or bacteria. A urine culture— which involves growing bacteria from your urine sample — is done less frequently. A urine culture can help identify which bacterium is causing the infection and what medication best targets that organism. If you've had a new sexual partner in the last few months, let your doctor know. In that case, your doctor may also check for sexually transmitted diseases.

In general, women who have a previous history of UTIs and are experiencing some of the classic symptoms (frequent, urgent or painful urination) can contact their physician for a prescription for antibiotics without needing to be seen in the doctor's office.

There are steps you can take to reduce your risk of future urinary tract infections. Drink plenty of liquids, especially water, to dilute your urine and flush bacteria from your urinary tract before an infection can begin. After urinating and after a bowel movement, wipe front to back to help prevent bacteria in the anal region from spreading to the vagina and urethra. Finally, empty your bladder soon after intercourse, and avoid using potentially irritating feminine products, such as deodorant sprays or powders, in the genital area.

— Paul Takahashi, M.D., Primary Care Internal Medicine, Mayo Clinic, Rochester, Minn.