Can UTI Lead to BV?
No, UTI does not lead to BV—the relationship works in the opposite direction: bacterial vaginosis significantly increases the risk of developing urinary tract infections.
The Directional Relationship
The evidence clearly demonstrates that BV is a risk factor for UTI, not the reverse:
- Women with bacterial vaginosis have a 2.79-fold increased risk of developing UTIs (odds ratio 2.79; 95% CI 1.05-8.33), with 22.4% of BV patients having concurrent UTI compared to only 9.7% without BV 1
- In one study, 75% of women with BV also had concurrent UTI, demonstrating a strong association where BV precedes or accompanies UTI 2
- BV-associated organisms have been recognized as agents causing urinary tract infections, suggesting these bacteria can ascend from the vagina to the urinary system 3
Why BV Increases UTI Risk
The pathophysiology explains this unidirectional relationship:
- BV involves replacement of protective H2O2-producing Lactobacillus species with anaerobic bacteria including Prevotella, Mobiluncus, and Peptostreptococcus species 4
- The rectum may serve as a reservoir for BV-associated flora, similar to the pathogenesis of UTIs, allowing these organisms to colonize both the vagina and urinary tract 3
- Loss of normal vaginal lactobacilli removes the protective barrier that prevents uropathogenic bacteria from ascending into the urinary system 4
Clinical Implications
When evaluating women with either condition, test for both:
- Women presenting with vaginitis should be screened for UTI, given the strong association 2
- Women with recurrent UTIs should be evaluated for BV as a potential contributing factor 1
- The normal flora of the periurethral area can be replaced by uropathogenic bacteria in the setting of BV, facilitating bacterial cystitis 4
Important Caveat
BV itself is not caused by UTI. BV results from disruption of normal vaginal ecology through factors including multiple sexual partners, douching, and lack of vaginal lactobacilli—not from urinary tract pathogens 4. The microbial, host, and social factors that lead to BV are distinct from those causing UTI 5.