Urinary Tract Infection - Risk Factors

Highlights	Risk Factors	Medications
Introduction	Complications	Other Treatments
Causes	Diagnosis	Resources
Symptoms	Treatment	References

Risk Factors

After the flu and common cold, urinary tract infections (UTIs) are the most common medical complaint among women in their reproductive years. Women are 30 times more likely to have UTIs than men are. Every year, 11% of American women have at least one such infection, and up to 60% of all women will develop a UTI at some time in their lives. A third of these women will have a recurrence within a year. Furthermore, each year about 250,000 women develop kidney infections (pyelonephritis) and 100,000 are hospitalized for treatment.

Structure of the Female Urinary Tract. In general, the higher risk in women is mostly due to the shortness of the female urethra, which is one and one half inches compared to eight inches in men. Bacteria from fecal matter can be easily transferred to the vagina or the urethra.

The female and male urinary tracts are relatively the same except for the length of the urethra.

text continues below

Sexual Behavior. Frequent or recent sexual activity is the most important risk factor for urinary tract infection in young women. Nearly 80% of all urinary tract infections occur within 24 hours of intercourse. (Sexual activity is less associated with cystitis in women after menopause.)

UTIs are very rare in celibate women. It is important to stress, however, that UTIs are not sexually transmitted infections, although these infections (e.g., Chlamydia trachomatis, gonorrhea, or herpes simplex virus) may increase the risk for UTIs.

In general, however, it is the physical act of intercourse itself that produces conditions that increase susceptibility to the UTI bacteria, with some factors increasing the risk.

Women having sex for the first time or who have intense and frequent sex after a period of abstinence are at risk for a condition called honeymoon cystitis.
A sudden increase in the frequency of sexual intercourse poses a significant risk for UTI, particularly if a diaphragm is used.
Sexual position (e.g., with the woman on top) can contribute to the risk.

Click the icon to see an image of a diaphragm.

Contraceptives may also contribute to risk in a number of ways:

The spring-rim of the diaphragm may bruise the area near the bladder neck, making it susceptible to bacteria.
Unlubricated condoms may injure vaginal tissue and make it vulnerable to infections. (Using a sterile water-based lubricant, such as KY jelly, may help reduce this risk. Petroleum-based lubricants should be avoided because they weaken latex condoms.)
Some women experience UTI as an allergic reaction to latex in condoms or to oral contraceptives.
Use of spermicide, such as nonoxynol-9, doubles or triples a women's risk for UTI, regardless of whether it is used with a condom or diaphragm. (Spermicides also pose a risk for sexually transmitted infections and experts warn against their use.)