Is BV a Sign of Cheating? The Truth About Sperm, pH, and Vaginal Health

Getting diagnosed with bacterial vaginosis (BV) can raise a hard question fast: did my partner cheat? Here's the short answer: BV on its own isn't a sign of cheating or proof that anyone cheated.

It's closely linked to sex, and new research suggests partners can pass BV bacteria back and forth. But it also shows up in monogamous couples, in women with female partners, and occasionally in women who have never had sex [1, 2].

Is BV a Sign of Cheating?

No. A BV diagnosis can't tell you whether anyone cheated, and the reasons are pretty convincing.

Most women with BV don't notice any symptoms at all [1], so it can be there for a while before anyone finds it. Finding it now doesn't tell you when it started, or who it came from.

BV also comes back often, even with the same partner. In a 2025 trial of monogamous couples, 63% of women whose partners weren't treated had BV again within 12 weeks [2]. Researchers think the bacteria linked to BV pass between partners during sex, so a couple can share them back and forth [2].

Can Sperm Cause BV?

Semen may make BV more likely, but it hasn't been shown to cause BV on its own. A healthy vagina is acidic, with a pH of about 3.8 to 4.5, thanks to the lactic acid made by Lactobacillus bacteria. Semen is alkaline, so sex without a condom can push your vaginal pH up for a while.

A higher pH makes life easier for the bacteria linked to BV. In a study of 248 South African women at high risk of HIV, 84% of those with signs of semen from the past 48 hours had shifted vaginal bacteria, compared with 66% of those without. But full BV was just as common in both groups, at about 1 in 3 [3].

That's a link, not proof that semen causes BV, and the exact cause of BV still isn't known [1]. The same study found that 70% of the women with semen present said they used condoms, but none said they used them every time, a good reminder that condoms only help when they're used consistently, start to finish [3].

Is BV an STD?

BV isn't officially classed as an STI, but the CDC says data "strongly demonstrate" that it spreads sexually between female partners, and evidence for male partners keeps growing [1, 4].

BV is more common with a new partner, more than one partner, female partners and not using condoms, and it's rare in women who have never had sex [1]. In 2025, a trial in The New England Journal of Medicine treated the male partners of women with BV too, with antibiotic pills and a cream for the penis for one week [2].

Recurrence was 35% when both partners were treated versus 63% when only the woman was, and the trial was stopped early because treating only the woman did clearly worse [2]. It was one open-label trial of 164 couples, and earlier trials that gave men antibiotic pills alone didn't lower recurrence, so experts are still working out who benefits [1, 2].

Later that year, ACOG, the main US group of OB-GYNs, updated its guidance on treating partners, citing a growing body of evidence that sex is an important way BV spreads [4].

How to Prevent BV?

There's no guaranteed way to prevent BV, but a few habits lower the odds. Using condoms every time keeps semen out of your vagina, and not using condoms is one of the known BV risk factors [1].

Skip douching, which is linked to BV too [1]. Your vagina cleans itself, so warm water on your vulva is enough, and if you share sex toys, clean them between uses [1].

If BV keeps coming back, ask your provider about longer-term treatment [1] and whether to treat your partner at the same time [4].

Supporting a Healthy pH, Inside and Out

Lactic acid is the same acid your good bacteria make, which is why it's used in products that support a healthy, acidic pH. Boric acid has been used in the vagina for decades, and when doctors prescribe it, the usual dose is 600mg [5].

At that dose, boric acid looks safe for women with healthy kidneys who aren't pregnant, but the data is limited, and no study has compared doses [5]. The review's authors feel boric acid should be prescribed by a provider, so check with yours before you start [5].

Neycher's Fresh & Soothed set pairs two hormone-free products. Odor Be Gone suppositories work inside, with lactic acid, 300mg boric acid (half the 600mg dose doctors usually prescribe) and 20mg hyaluronic acid for moisture. HydroBloom Gel soothes and hydrates your vulva on the outside.

They're for freshness and comfort, not a replacement for a doctor's care. If you notice new odor or unusual discharge, see your provider before trying them.

How to use them safely

Use one suppository at bedtime for 10 nights in a row, then as needed, and skip it during your period. Use the gel once a day for 6 days in a row, then every few days as needed.

The suppositories are for vaginal use only, so never swallow them, and keep them away from kids [5].

Boric acid isn't recommended during pregnancy, so if you're pregnant or trying to get pregnant, check with your doctor before use [5]. After giving birth, wait for your checkup and your doctor's okay before you put any product in your vagina. If you're breastfeeding, check with your doctor first.

If you have kidney problems, or sores or broken skin in or around your vagina, talk to your doctor before use, since it's not clear how much boric acid gets absorbed through damaged tissue [5]. If anything stings or burns, stop using it.

Using condoms? Read this first

Both products contain oils: the suppositories have a fatty base plus tea tree oil and vitamin E, and the gel contains linseed oil. Oil-based vaginal products might weaken latex condoms and diaphragms, which can make a condom more likely to break [1].

For a similar oil-based vaginal suppository, the CDC advises not relying on condoms or diaphragms for 72 hours after use [1]. So any time you use the suppositories, and for three days after, don't count on latex condoms or diaphragms for birth control or STI protection.

The gel has only a small amount of oil, but don't rely on latex condoms right after using it either. If you could get pregnant, use another kind of birth control too.

Your BV and Cheating Questions, Answered

My boyfriend gave me BV. Is that possible?

It can work that way. Evidence suggests the bacteria linked to BV can pass between partners during sex [2], which is also why BV can keep coming back with the same partner.

It doesn't mean he cheated, since a steady partner can share these bacteria with you too [2]. Here's more on whether men get BV.

Can I get BV from a female partner?

Yes, BV is linked to having female partners too [1], so it isn't only about men or semen.

Can I have sex while I'm being treated for BV?

The CDC advises skipping sex or using condoms every time during BV treatment [1]. If your treatment is a cream or suppository, ask whether it's oil-based, since some can weaken latex condoms for days after use [1].

Should my partner get treated?

If your BV keeps coming back and you have a regular male partner, ask your provider about treating him at the same time. ACOG's 2025 guidance covers when this makes sense [4].

How to Talk About BV Without Blame

If BV is causing tension at home, share the facts: it's common, it often has no symptoms, and couples can pass it back and forth without anyone cheating [1, 2].

Then book a visit. A provider can confirm it's BV and not something else, treat it, and talk through whether your partner should be treated too [4]. If you're pregnant, call right away, since BV in pregnancy is linked to preterm birth [1].

BV is something to handle together, not proof of anything.

This article is for educational purposes only. It is not meant to replace professional medical advice. Always talk to your doctor about any health questions.

Keep reading

• What is Bacterial Vaginosis?
• How Long Can a Man Carry BV?
• Do Men Get BV?

References

[1] Workowski, K. A., Bachmann, L. H., Chan, P. A., Johnston, C. M., Muzny, C. A., Park, I., Reno, H., Zenilman, J. M., & Bolan, G. A. (2021). Sexually transmitted infections treatment guidelines, 2021. MMWR Recommendations and Reports, 70(4), 1-187. PMID: 34292926. https://pmc.ncbi.nlm.nih.gov/articles/PMC8344968/

[2] Vodstrcil, L. A., Plummer, E. L., Fairley, C. K., Hocking, J. S., Law, M. G., Petoumenos, K., Bateson, D., Murray, G. L., Donovan, B., Chow, E. P. F., Chen, M. Y., Kaldor, J., & Bradshaw, C. S. (2025). Male-partner treatment to prevent recurrence of bacterial vaginosis. The New England Journal of Medicine, 392(10), 947-957. PMID: 40043236. https://pubmed.ncbi.nlm.nih.gov/40043236/

[3] Mngomezulu, K., Mzobe, G. F., Mtshali, A., Osman, F., Liebenberg, L. J. P., Garrett, N., Singh, R., Rompalo, A., Mindel, A., Karim, S. S. A., Karim, Q. A., Baxter, C., & Ngcapu, S. (2021). Recent semen exposure impacts the cytokine response and bacterial vaginosis in women. Frontiers in Immunology, 12, 695201. PMID: 34177961. https://pmc.ncbi.nlm.nih.gov/articles/PMC8221111/

[4] American College of Obstetricians and Gynecologists. (2025). Concurrent sexual partner therapy to prevent bacterial vaginosis recurrence. Obstetrics & Gynecology, 146(6), e111-e114. PMID: 41100865. https://pubmed.ncbi.nlm.nih.gov/41100865/

[5] Mittelstaedt, R., Kretz, A., Levine, M., Handa, V. L., Ghanem, K. G., Sobel, J. D., Powell, A., & Tuddenham, S. (2021). Data on safety of intravaginal boric acid use in pregnant and nonpregnant women: A narrative review. Sexually Transmitted Diseases, 48(12), e241-e247. PMID: 34561373. https://pmc.ncbi.nlm.nih.gov/articles/PMC10100571/