Reconsidering the Role of Male Partners in Recurrent Bacterial Vaginosis

 

Dr. Kim Capone, Lead educator of SHWI and Chief Science Officer for Vaginal Biome Science.

 

 

 

Bacterial vaginosis (BV) remains the most common cause of vaginal discharge among reproductive-age women and continues to present a major challenge due to high rates of recurrence, reportedly affecting up to 60% of women within 12 months following standard treatment¹. Despite growing evidence implicating sexual transmission of BV-associated organisms, treatment strategies have largely focused on the female partner alone.

A recent randomized, multicenter trial published in The New England Journal of Medicine offers compelling evidence in favor of revising this approach. In the study, female participants whose regular male partners received combination therapy of oral metronidazole and topical clindamycin demonstrated significantly lower recurrence rates (35%) at 12 weeks, compared to 63% in the standard care group².

These findings stand in contrast to earlier studies that failed to show benefit from treating male partners. For instance, a 2021 double-blind, placebo-controlled trial of oral metronidazole in male partners yielded no improvement in recurrence outcomes among female participants³. A 2012 systematic review also concluded that male treatment, as tested in prior trials, did not improve BV outcomes in women⁴. The critical differentiator in the new study was its dual-route regimen, targeting both urethral (via oral therapy) and external penile (via topical therapy) reservoirs of BV-associated bacteria with antibiotics.

However, the generalizability of these findings warrants consideration. The trial was conducted in Australia, where more than 90% of male participants were uncircumcised, which is a known factor associated with increased colonization by Gardnerella and other BV-associated organisms. In contrast, circumcision rates are significantly higher in North America. Additionally, 26% of the women enrolled were using an intrauterine device (IUD), which has been associated with increased BV risk and recurrence. These population characteristics may influence the extent to which these results translate to other settings and patient populations¹⁴.

While BV is not formally classified as a sexually transmitted infection, the recurrence patterns and this latest evidence suggest a mixed pathogenesis whereby BV may result from intrinsic disruptions of the vaginal microbiota or be maintained or reintroduced through sexual contact. It is not universally sexually transmitted, but it can be, and likely is, in many cases. As such, the failure to engage male partners in treatment may be a key factor perpetuating recurrence in select patient populations.

Epidemiologic data further support this shift. Incident BV has an incubation period similar to bacterial STIs⁵ and is strongly associated with new sexual partners⁶⁻⁷. Recurrence risk is roughly doubled among women with regular male partners⁸⁻⁹. Multiple studies show that men can harbor BV-associated bacteria including Gardnerella and Prevotella in the distal urethra and under the foreskin¹⁰⁻¹¹. Importantly, the penile microbiota has been shown to predict a female partner’s risk of BV¹². Prior trials of male treatment were limited by small sample sizes, lack of adherence monitoring, and reliance on oral therapy alone⁴,¹³. These limitations are directly addressed in the recent study through the addition of topical antibiotics.

While dual antibiotic therapy showed efficacy, this raises important questions about the long-term sustainability of repeated antimicrobial use, particularly in the context of rising antibiotic resistance. Notably, interventions such as improved male genital hygiene have not demonstrated consistent clinical benefit to date, though more rigorous evaluation is warranted. Still, it is reasonable to hypothesize that combined hygiene practices, particularly those that support microbial balance and biofilm disruption in women and their partners, may eventually serve as adjunctive or preventive measures.

Finally, BV is a polymicrobial condition, and the risk of recurrence or reinfection likely varies depending on the dominant organisms involved. Future approaches may incorporate species-specific diagnostics to detect the particular microbes present and personalized treatment strategies, both for the woman and her partner.

Clinical Implication: The recent trial marks a potential shift in the BV treatment paradigm and supports a couple-centered approach to management in some cases.  In recurrent cases, especially within monogamous partnerships, clinicians should consider engaging male partners in both oral and topical treatment and/or hygiene protocols. While further studies are needed in more diverse populations, this evidence signals a critical opportunity to break the cycle of recurrence through coordinated partner care.

 

References

1. Bradshaw CS, Morton AN, Hocking J, et al. High recurrence rates of bacterial vaginosis over the course of 12 months after oral metronidazole therapy and factors associated with recurrence. J Infect Dis. 2006;193(11):1478–86.
2. Vodstrcil LA, Plummer EL, Fairley CK, et al. Male-partner treatment to prevent recurrence of bacterial vaginosis. N Engl J Med. 2025;392:947–57.
3. Schwebke JR, Lensing SY, Lee J, et al. Treatment of male sexual partners of women with bacterial vaginosis: a randomized, double-blind, placebo-controlled trial. Clin Infect Dis. 2021;73(3):e672–e679.
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