You did everything right…You finished the full course of antibiotics, you didn't stop early even though the symptoms cleared up after day three, and you skipped sex until you were feeling back to normal. And yet, a few weeks (or months) later, that familiar fishy odor and unusual discharge are back. 

Recurrent bacterial vaginosis (BV) is incredibly common. Research shows more than half of people treated for BV will have it come back within a year, and for a lot of people, it returns within just a few months of finishing treatment. So if you're stuck in a cycle of "get treated, feel better, get BV again," here's what's actually going on, and why the newest research says your partner might be part of the equation.

What is BV?

BV isn't an infection in the traditional sense; it's a disruption of your vaginal microbiome. Your vagina is home to protective bacteria called lactobacilli, which keep things acidic and inhospitable to anything harmful. BV happens when that balance tips: lactobacilli drop, and "bad" anaerobic bacteria (most commonly Gardnerella vaginalis) take over.

Why does BV keep coming back?

Antibiotics don't always finish the job. Standard BV treatment (usually metronidazole or clindamycin) kills off the harmful bacteria, but it doesn't necessarily restore your lactobacilli or fully break down biofilm, a protective layer some BV-causing bacteria build that lets them survive treatment and repopulate later.

Your microbiome never fully bounces back. Even after symptoms disappear, your vaginal flora can stay in a fragile, imbalanced state, which makes it easier for BV to return the next time something disrupts it, like your period, a new partner, or a stressful month.

Everyday habits keep tipping the scale. Douching, scented soaps or washes, tight synthetic underwear, smoking, and IUDs have all been linked to higher BV recurrence. None of these things are "wrong" to do, but they can all shift your vaginal pH in a direction that favors BV.

And, increasingly, the research points to partners.

Here's the piece that's finally getting real scientific attention. For years, doctors weren't sure why BV kept bouncing back in people with the same sexual partner. A landmark study published in the New England Journal of Medicine in 2025 gives us a compelling answer: the bacteria that cause BV can live on a male partner's penile skin and in the urethra, without causing him any symptoms at all, and get passed right back during sex.

In the study, researchers gave women with BV standard treatment, and randomly assigned their male partners to either receive treatment too (both an oral antibiotic and a topical cream) or no treatment at all. The results were striking: only 35% of women whose partners were also treated had BV come back within 12 weeks, compared to 63% of women whose partners weren't treated. The trial was actually stopped early because the difference was so clear it wouldn't have been ethical to keep the control group untreated.

This tracks with what researchers have found when they've swabbed male partners directly: many carry Gardnerella and other BV-associated bacteria on the penis or in the urethra with zero symptoms of their own, since men's bodies don't tend to react to these bacteria the way vaginal tissue does. That's the frustrating part: he can feel completely fine and still be part of the reason it keeps coming back.

To be clear, BV still isn't classified as an STI, and partner treatment isn't yet standard medical guidance. But this research is a big deal, and it's worth bringing up with your provider, especially if you're dealing with recurrent BV and you're in a monogamous relationship.

What to do if you have BV

• Talk to your provider about recurrent BV specifically. Recurring cases are sometimes treated differently than a one-off, including longer treatment courses or maintenance regimens.
• Bring up partner treatment. Ask your provider whether it makes sense for your partner to be evaluated or treated alongside you, particularly if this keeps happening with the same partner.
• Support your microbiome, don’t just treat the symptoms. A vaginal probiotic with the right lactobacilli strains can help rebuild your natural flora after antibiotics, rather than leaving your vagina in that vulnerable in-between state.
• Rule out what you're actually dealing with. BV and yeast infections can look similar but need totally different treatments. An at-home vaginal pH test can help you figure out which one you're facing before you treat it.
• Revisit the basics. Skip douching and scented products, stick to cotton underwear, and use condoms if you're trying to reduce bacterial exchange during this stretch.

Recurrent BV isn't a hygiene failure or something you're doing wrong. It's a microbiome issue, and often, it's a shared one. The more researchers learn, the clearer it becomes that treating BV as a "just her" problem misses half the picture. If it keeps coming back, it might be time to widen the conversation, and the treatment plan, to include your partner too.

Questions about BV, testing, or what to try next? We're here for it. Check out our Vaginal Health Test + Treat to figure out what you're dealing with, and our Male BV Treatment to keep the infection from coming back!