Urinary tract infections result from bacterial infections of the bladder, kidney or urethra, the tube connecting the bladder to the outside of the body. Women are more likely to develop urinary tract infections. Approximately 20 percent of all women develop a urinary tract infection at some point in their life, according to the National Kidney and Urologic Diseases Information Clearinghouse. Although doctors do not fully understand the reasons behind urinary tract infections, some causes are known.
Sexual Intercourse
Women have a much shorter urethra then men, which increases the risk that bacteria can travel from outside the body, up the urethra and into the bladder. Sexual intercourse increases the risk of a urinary tract infection, most likely because bacteria is pushed from the vagina into the urethra, explains WomensHealth.gov. In addition, the use of a diaphragm for birth control has been linked to an increased risk of a urinary tract infection, as is the use of spermicidal lubricants.
Behaviors
Women's urethras are also much closer to the anus than in men, which means that bacteria from the anus are more likely to reach the urethra. Wiping with toilet paper from the back to the front following a bowel movement can increase the risk of transferring bacteria from the anus to the urethra, WomensHealth.gov explains. In addition, waiting too long to urinate causes urine to remain in the bladder for a long time, giving bacteria more time to grow.
Urinary Obstructions
Any condition that hinders the flow of urine through the urinary tract increases the risk of a urinary tract infection. For example, kidney stones block urine from passing through the urinary tract and cause an infection. Some women are born with physical abnormalities of the urinary tract, such as narrow ureters, the tubes that connect the kidneys to the bladder. These conditions can cause urinary tract infections early in life, reports Medline Plus.
Menopause and Pregnancy
Women who have reached menopause often experience increased urinary tract infections, according to the Mayo Clinic. The reduced levels of estrogen result in changes to the urinary tract that leaves it more susceptible to bacterial infection. In addition, the changes that occur in women during pregnancy increase the risk of urinary tract infections in the kidneys, but does not increase the risk to other parts of the urinary tract.
Diseases
Some diseases, such as diabetes, that compromise the immune system increase the risk of urinary tract infections, because the body cannot kill the invading bacteria. Furthermore, other medical conditions that require the insertion of a catheter to remove urine from the body can result in an increased frequency of urinary tract infections from the bacteria on catheters.
