A urinary tract infection, or UTI, is an illness that occurs when bacteria infect the urinary tract.
Most UTIs involve infection of the lower urinary tract, which includes the bladder and urethra (the tube through which urine passes out of the body).
Less often, UTIs involve the upper urinary tract, which includes the kidneys and ureters (tubes connecting the kidneys to the bladder).
Cystitis is the name for a UTI that infects the bladder, and urethritis is a UTI that infects the urethra.
Pyelonephritis is the name for a UTI infecting the kidneys, a potentially serious infection.
UTIs are very common, accounting for nearly 10 million doctor visits in the United States each year.
Women and girls get UTIs more often than men and boys. This is due to differences in anatomy that include:
A shorter urethra
A moister environment around the urethral opening
A urethral opening that's closer to the anus
About one in five women will have a UTI at some point.
Sexually active women are more likely to get UTIs than women who aren't sexually active.
One study of women in college found that those who'd had sexual intercourse on one day in the last week were 37 percent more likely to get a UTI — and those who'd had sex on five days were almost five times as likely to get one — as those who hadn't had sex.
UTIs are especially rare in young and middle-aged adult men. For every 10,000 healthy men in this age group, only about five to eight experience UTI symptoms each year.
UTI Causes and Risk Factors
UTIs begin when bacteria enter the urinary tract. These germs usually get in through the urethra.
Most UTIs are caused by E. coli and other bacteria that are normally found in the digestive tract.
Sexually transmitted infections — including herpes, gonorrhea, chlamydia, and mycoplasma — can also cause UTIs.
The following risk factors increase your chance of getting a UTI:
Having a shorter urethra
Improper wiping, in women and girls (wiping from back to front can bring bacteria from the anus into the urethra)
Having an enlarged prostate or benign prostatic hyperplasia (BPH) in men
Not urinating much due to low intake of fluids
Kidney stones or other blockages of the urinary tract
Using diaphragms or spermicidal agents for birth control
Menopause, which causes changes in the urinary tract in women
Using a catheter to urinate
Recent surgery or another medical procedure involving the urinary tract
Having diabetes or another disease that suppresses the immune system
UTIs During Pregnancy
UTIs aren't any more common in pregnant women than in other women, but they can be more difficult to get rid of and more inclined to come back.
A UTI during pregnancy may also be more serious.
This is because pregnancy causes changes to the urinary tract that make it easier for the kidneys to become infected.
If you're pregnant and suspect you may have a UTI, seek medical attention quickly.
Most UTIs cause no lasting damage if they're treated quickly.
But untreated UTIs can lead to complications, including:
Permanent kidney damage
Greater risk of premature or low-birth-weight babies in pregnant women
Narrowing of the urethra in men
A potentially life-threatening infection called sepsis, especially when kidneys are infected (called urosepsis)
These are several steps you can take to reduce your risk of getting a UTI:
Drink plenty of water and other liquids, to help flush out bacteria
Don't delay urinating any longer than necessary
Wipe from front to back after urinating or having a bowel movement
Urinate soon after having sexual intercourse
Avoid vaginal deodorants, douches, powders, and other potentially irritating feminine products
Use a method of birth control other than a diaphragm, spermicide, or unlubricated condoms
Drinking cranberry juice is often recommended as a way to help prevent UTIs.
Although studies haven't proven that cranberry juice is effective for this purpose, drinking it probably won't hurt, either.