How can lower estrogen levels affect the urinary tract’s defenses against infection?

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The most common cause of urinary tract infection is invasion into the urethra of Escherichia coli, a type of bacterium that normally inhabits the bowel. — urinary tract infection The most common cause of urinary tract infection is invasion into the urethra of *Escherichia coli*, a type of bacterium that normally inhabits the bowel.

Lower estrogen levels can compromise the body's natural defenses against infection by altering the vaginal environment. Under the influence of estrogen, the vaginal lining maintains a thickness and elasticity that supports a healthy ecosystem. Specifically, these cells contain glycogen, which beneficial bacteria ferment to produce lactic acid.1

This production of lactic acid creates a slightly acidic environment that acts as a protective barrier against disease-causing microorganisms. When estrogen levels decline, such as in older women, the vaginal lining may thin and the production of glycogen—and subsequently lactic acid—may decrease. This reduction in acidity weakens the protective barrier, potentially increasing susceptibility to infections that can affect the surrounding pelvic structures, including the urinary bladder.1