Bacterial vaginosis: male-partner treatment may prevent recurrence
Published in The New England Journal of Medicine, March 2025.
Introduction
Bacterial vaginosis (BV) is a common vaginal infection affecting approximately 1 in 3 reproductive age women worldwide at some point in their life1. Symptoms can vary, but most commonly include a grey-white, thin discharge, often with a ‘fishy’ odour.
BV is characterised by a change in vaginal pH and an imbalance in the vaginal microbiome, often with reduced numbers of lactobacilli and a proliferation of BV-associated bacteria such as Gardnerella and Prevotella 2. Left untreated BV can be associated with fertility issues, recurrent miscarriage, and pelvic inflammatory disease3.
Conventional treatment is with an oral antibiotic. However, more than 50% of women experience a recurrence of BV within 6 months of treatment2. The findings of a new study comparing female and male-partner treatment for BV with standard female-only treatment go some way towards explaining why this may be the case
Methods
This was an open-label, randomized controlled trial involving monogamous, heterosexual couples in which the female partner had BV.
81 couples were assigned to the partner-treatment group in which the woman received standard oral antimicrobial medication, and the male partner received oral and topical antimicrobial medication (metronidazole 400-mg tablets and 2% clindamycin cream applied to penile skin, both twice daily for 7 days).
In the control group (83 couples) only the female partner received antimicrobial medication.
The primary outcome measure was recurrence of BV within 12 weeks.
Results
The trial was stopped by the data and safety monitoring board after only 150 couples had completed the 12-week follow-up because the female-only treatment was significantly inferior to the combined male and female treatment.
In the control group with female-only treatment, BV recurred in 63% of women who completed the trial. In the partner treatment group, BV recurred in only 35% of women. In addition, the average length of time before infection recurred was longer when both partners were treated.
Conclusion
Compared to current treatment practices, prescribing antimicrobial medication for both partners in a heterosexual relationship appears to result in much lower rates of BV recurrence after three months.
Key clinical takeaways
Until now there has been limited clear evidence to show that men can carry and transmit BV-associated bacteria. While acknowledging that sex is one of several potential triggers for BV, these findings show that BV is more than just a female health issue and can be a sexually transmitted infection. This study highlights the significance of external influences on the vaginal microbiome and the importance of microbial support for both partners when managing BV.
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