If you have a vagina, you’ve probably experienced vaginal discomfort at some point. You may know how to spot the symptoms of thrush or cystitis, but if there’s a persistent fishy smell or an unusual discharge, it could be bacterial vaginosis (BV). A common yet often misunderstood condition, BV affects approximately one in three people with a vagina at some point in their lives (Vodstrcil et al., 2025).
What is Bacterial Vaginosis?
Bacterial vaginosis occurs when the balance of bacteria in the vagina is disrupted, leading to an overgrowth of anaerobic bacteria. Unlike thrush, which is caused by yeast overgrowth, BV is linked to an imbalance in bacterial communities. Symptoms include:
- Increased vaginal discharge (often grey or white)
- A strong, fishy odour (especially noticeable after sex)
- Mild irritation or burning during urination
- No itching (which is more commonly associated with thrush or STIs)
Interestingly, about half of those with BV experience no symptoms, which makes diagnosis and treatment even more challenging.
What Causes BV?
BV isn’t classified as a sexually transmitted infection (STI), but sexual activity is a significant risk factor. Around 85% of those who develop BV are sexually active, and certain sexual practices can increase susceptibility. Key risk factors include:
- Having new or multiple sexual partners
- Not using condoms or dental dams
- Engaging in vaginal sex after anal sex without changing condoms
- Vaginal douching or using scented products
- Changes in hormone levels (e.g., due to contraception or menstrual cycle changes)
- Prolonged or irregular bleeding from hormonal contraception
Why is BV Recurrence So Common?
Many people find BV frustratingly persistent. Standard treatment typically involves antibiotics like metronidazole or clindamycin, but recurrence rates are high—up to 50% of people experience BV again within six months of treatment (Vodstrcil et al., 2025). Until recently, treatment has focused solely on the affected person, without addressing potential bacterial exchange with male partners.
New Research: Should Male Partners Be Treated?
A groundbreaking study published in the New England Journal of Medicine (Vodstrcil et al., 2025) investigated whether treating male partners could reduce BV recurrence. This open-label, randomized, controlled trial included couples where the woman had BV and was in a monogamous relationship with a male partner.
Study Design:
- Partner-Treatment Group: Women received standard BV treatment, and their male partners took oral metronidazole (400 mg twice daily) and applied 2% clindamycin cream to the penis for seven days.
- Control Group: Women received standard treatment, but their partners were not treated.
- The primary outcome was BV recurrence within 12 weeks.
Key Findings:
- BV recurrence was significantly lower in the partner-treatment group (35%) than in the control group (63%).
- Recurrence rates were 1.6 per person-year in the partner-treatment group versus 4.2 per person-year in the control group.
- Treating male partners reduced absolute BV recurrence risk by 2.6 recurrences per person-year.
- Some men in the study reported mild side effects from treatment, including nausea, headaches, and a metallic taste.
These results were compelling enough that the trial was stopped early because treating the male partner was shown to be far superior to treating the woman alone.
What This Means for BV Treatment
For decades, BV treatment has largely ignored male partners, under the assumption that they do not contribute to reinfection. However, this study provides strong evidence that treating male partners may significantly reduce recurrence rates. While further research is needed to refine treatment protocols, this study suggests a potential shift in how BV is managed.
How Can You Prevent BV Recurrence?
If you struggle with recurrent BV, here are some strategies that may help:
- Practice Safer Sex: Use condoms or dental dams to reduce bacterial transfer between partners.
- Avoid Vaginal Douching and Scented Products: These can disrupt the vaginal microbiome.
- Consider Male-Partner Treatment: If you have a male partner and experience recurrent BV, discuss this new research with your doctor.
- Support Vaginal Health: Probiotic supplements with Lactobacillus crispatus may help maintain a healthy vaginal microbiome.
- Manage Hormonal Changes: If BV flares up with hormonal contraception, speak with your healthcare provider about alternatives.
The Bottom Line
Bacterial vaginosis is an extremely common yet frustrating condition. Until now, treatment has focused solely on the person with BV, but new research suggests that treating male partners could dramatically reduce recurrence rates. If you experience persistent or recurrent BV, talk to your healthcare provider about the latest evidence and whether partner treatment might be a viable option for you.
By breaking the cycle of BV recurrence, this new approach offers hope for many people struggling with this condition. While more research is needed, this study represents an important step forward in women’s health and STI prevention.
Sources
- Vodstrcil, L. A., Plummer, E. L., Fairley, C. K., Hocking, J. S., Law, M. G., Petoumenos, K., Bateson, D., et al. (2025). Male-partner treatment to prevent recurrence of bacterial vaginosis. New England Journal of Medicine, 392(10), 947-957. https://doi.org/10.1056/NEJMoa2405404
