Does My Partner Need to Be Treated for BV? What the 2025 Research Says

You finish the antibiotics. Things feel normal for a few weeks. Then, often right after sex with the same partner, it's back.

If that loop sounds familiar, you're not imagining the pattern, and you're not doing anything wrong. For decades, BV was handled as a problem that lived in one body. New research suggests the other half of the picture matters too.

Why does BV keep coming back after treatment?

Recurrence is the rule, not the exception. A 2026 review in Current Opinion in Infectious Diseases states: "Standard antibiotic therapy often induces symptom remission, but recurrence rates exceed 50% within 6 months" (Kim et al., 2026).

There are several reasons BV returns, from biofilms that antibiotics don't fully clear to changes in the vaginal microbiome after treatment. One reason that got a lot more attention in 2025 is a partner who carries some of the same bacteria.

Can men carry BV bacteria?

Yes. Men don't get "BV" because it's a condition of the vagina, but the penis has its own microbiome, and it can hold bacteria that are linked to BV.

A 2026 narrative review in Clinical Microbiology Reviews summarizes it this way: "In the few studies that simultaneously evaluate the penile and vaginal microbiome in sex partners, specific taxa are highly correlated, with evidence for bi-directional transmissibility" (Mehta, 2026).

In plain terms, bacteria can move both ways between partners. That's the BV ping pong many couples describe.

An earlier study of 168 couples in Kenya went further. It looked at the man's penile bacteria first, then followed the women who didn't have BV at the start. The authors concluded: "Baseline penile microbiota accurately predicted BV incidence in women who did not have BV at baseline" (Mehta et al., 2020). They also found BV was more common when the man was uncircumcised (37.3%) than circumcised (26.3%).

You might be thinking: but he feels completely fine. That's common. Carrying these bacteria may not cause anything he would notice, which is one reason partners get overlooked.

What did the 2025 NEJM partner-treatment study find?

The StepUp trial, run by the Melbourne Sexual Health Centre and published in the New England Journal of Medicine in March 2025, is the study that changed the conversation (Vodstrcil et al., 2025).

In the study's own words, the trial "was stopped by the data and safety monitoring board after 150 couples had completed the 12-week follow-up period because treatment of the woman only was inferior to treatment of both the woman and her male partner."

What the men in the study received: "metronidazole 400-mg tablets and 2% clindamycin cream applied to penile skin, both twice daily for 7 days." The study reported side effects in treated men including "nausea, headache, and metallic taste." This is what the researchers tested, not a recommendation. Only a clinician can tell you whether any treatment is right for you or your partner.

Here's the part that matters. Earlier partner trials mostly gave men a single oral antibiotic and found no benefit. StepUp added a cream applied directly to the penis, which reaches the skin bacteria a pill may miss.

We broke this study down on Instagram:

Watch this video on Instagram

What do ACOG and the CDC say now?

This is where people get confused, because the guidance is in the middle of changing.

• ACOG (October 2025): According to the 2026 review above, "the American College of Obstetricians and Gynecologists now advises partner therapy for recurrent BV, signaling a shift toward partner-inclusive management strategies" (Kim et al., 2026).
• CDC (page last reviewed July 2021): The CDC's treatment guideline still says "routine treatment of sex partners is not recommended" (CDC). That page predates StepUp.

So if one clinician says "your partner doesn't need anything" and another says "let's treat you both," both are following real guidance. The newer evidence supports including the partner when BV keeps returning.

Who does partner treatment apply to?

Based on who was in the StepUp trial, the strongest evidence is for:

1. Women with BV who keep getting it back (recurrent BV)
2. In a monogamous relationship
3. With one regular male partner

The research doesn't yet tell us much about women with female partners, people with several partners, or BV without symptoms. The 2026 Clinical Microbiology Reviews paper notes: "Optimal and non-optimal PMB have not been defined" (PMB means penile microbiome). In other words, science is still mapping what a healthy penile microbiome looks like.

Is BV an STD?

BV is not officially classed as an STI. But the evidence that sex plays a role keeps growing. The 2026 review describes "strong evidence supporting transmission of bacteria associated with the dysbiotic state of BV between sexual partners" (Kim et al., 2026).

This isn't about blame. Nobody "gave" anyone anything on purpose. It's just two microbiomes that share space.

What can couples do if BV keeps coming back?

• Talk to your clinician about partner therapy, and mention the 2025 NEJM StepUp trial and ACOG's update by name. Some clinicians haven't seen it yet.
• Bring your partner into the conversation. He may need his own appointment or prescription.
• Hold off on sex during treatment if your clinician advises it. Couples in StepUp were asked to.
• Track the pattern. Note when symptoms come back (after your period, after sex, with a new partner). It helps your clinician spot what's driving it.
• Learn what's in both microbiomes. If you want to understand your bacteria and your partner's side by side, an at-home microbiome test can give you a starting point for that conversation.

The 60-second version, if you want to send it to your partner:

Watch this video on Instagram

Seeing both sides of the picture

Almost every vaginal microbiome test on the market looks at one person. That made sense when BV was treated as a one-body problem. The 2025 research says the couple is the unit.

That's why we built the Anteros Partner Test: two people swab at home, and you see both microbiomes side by side in one report. Testing on your own? The Eros Solo Test works for anyone, any body.

Anteros tests are for wellness and informational use. They do not diagnose or treat any condition and do not test for STIs. Share your results with your clinician.

Frequently asked questions

Is my partner cheating if I keep getting BV? Not necessarily. BV isn't classed as an STI, and it often comes back with no new partner involved. In the StepUp trial, BV came back within 12 weeks in 63% of women in monogamous couples when only the woman was treated. Repeat BV with the same partner is common and doesn't prove infidelity.

Does my boyfriend need to be treated for BV if I have it? Not always. Partner therapy has the strongest evidence for recurrent BV in a monogamous relationship with a male partner. If your BV keeps returning, ask your clinician about treating your partner too.

Can my partner keep giving me BV back? Research suggests BV-linked bacteria can pass in both directions between partners, which may contribute to repeat episodes. In the StepUp trial, treating male partners cut recurrence from 63% to 35% within 12 weeks.

Can men carry BV? Men don't get BV, because it's a condition of the vagina. But the penis can carry bacteria linked to BV, often without anything he would notice. That's one reason partners get overlooked when BV keeps coming back.

Can men carry BV in their sperm? Studies have found BV-associated bacteria on penile skin and at the urethral opening. The research focuses on these sites rather than semen alone, and it is still developing.

How do men get tested for BV? There's no standard clinical BV test for men. Researchers say tests for the penile microbiome still need to be developed for screening and monitoring. If your BV keeps coming back, your clinician may treat your partner based on your history.

How do I tell my partner I have BV? Keep it simple and blame-free: BV is common, it isn't an STI, and new research suggests partners can share the bacteria. Sharing the NEJM study can make the conversation about solving it together, not about who caused it.

Does partner treatment apply to same-sex couples? StepUp only studied women with male partners, so the evidence doesn't yet cover same-sex couples. More research is needed.

Sources

1. Vodstrcil LA, et al. Male-Partner Treatment to Prevent Recurrence of Bacterial Vaginosis. N Engl J Med. 2025;392(10):947–957. https://doi.org/10.1056/NEJMoa2405404
2. Kim ES, Waltmann A, Duncan JA, Hood-Pishchany I. Advances in treating bacterial vaginosis: recognizing sexual transmission and pipeline of therapies. Curr Opin Infect Dis. 2026;39(1):67–74. https://doi.org/10.1097/QCO.0000000000001172
3. Mehta SD. Role of the penile microbiome in female sex partner risk of bacterial vaginosis and sexually transmitted infections: a narrative review. Clin Microbiol Rev. 2026;39(3):e0033125. https://doi.org/10.1128/cmr.00331-25
4. Mehta SD, et al. The Microbiome Composition of a Man's Penis Predicts Incident Bacterial Vaginosis in His Female Sex Partner With High Accuracy. Front Cell Infect Microbiol. 2020;10:433. https://doi.org/10.3389/fcimb.2020.00433
5. Centers for Disease Control and Prevention. Bacterial Vaginosis: STI Treatment Guidelines (last reviewed July 22, 2021). https://www.cdc.gov/std/treatment-guidelines/bv.htm

This article is for general education and is not medical advice. Talk to a licensed clinician about symptoms, testing and treatment. Last updated: October 2026.