WTF is BV?!

Bacterial vaginosis (BV) is one of those conditions everyone’s heard of, but few really understand. Often dismissed as a mild infection or “just a bit off,” BV actually tells a deeper story about the vaginal microbiome, sexual connections, and reproductive health.

At its core, BV is a shift in the vaginal ecosystem. In a healthy vagina, lactobacilli dominate, keeping things acidic and producing protective compounds like lactic acid and hydrogen peroxide. When lactobacilli drop, other bacteria such as Gardnerella, Fannyhessea (Atopobium), and Prevotella move in, thrive in a more alkaline environment, and form sticky biofilms that are tricky to clear. Symptoms like discharge, odour, or irritation may appear, but often there is nothing at all. Around 50 to 80 percent of people with BV do not notice anything [1-3].

BV is not classified as an STI, but it is closely linked to sexual activity. Partners can share microbes, making recurrence common if only one side is treated. BV is more frequent with new or multiple partners and less common with consistent condom use [4-8].

This bacterial shift does not just affect the vagina, it can influence the whole reproductive landscape. Fewer lactobacilli mean more inflammation and oxidative stress, creating conditions that favour pathogens and increase the risk of STIs, pelvic inflammatory disease, and even endometritis [9-13]. For fertility, this matters. The vaginal microbiome is the first line of defence for sperm, shaping the environment they encounter. BV-associated biofilms can reduce sperm motility and survival, quietly interfering with conception.

Recent research shows BV bacteria can appear in semen, making men potential reservoirs for reinfection [4,6]. BV is a shared microbial story, affecting straight and same-sex couples alike, and treating both partners, when relevant, helps break the cycle.

There is also growing evidence linking BV to HPV persistence and cervical abnormalities. A low-lactobacillus, high-diversity environment makes it harder for the immune system to clear HPV, with inflammation and mucus changes contributing to risk [9,11].

Addressing BV is not just about antibiotics or symptom relief, it is about rebuilding the ecosystem. Proper testing, including vaginal and seminal microbiome analysis, shows which species are dominating and guides a targeted approach. Breaking down biofilms, treating partners when needed, and restoring beneficial bacteria, particularly Lactobacillus crispatus, are key. Supporting your microbes with nutrition and lifestyle choices sets the stage for long-term balance.

BV is more than “a smell” or “a nuisance infection.” It is a clue, inviting us to listen to our bodies and the microbial communities that support them. Recurrent BV, fertility challenges, or unexplained microbial imbalance, testing and targeted support can help you reclaim balance. Your microbes are telling a story, time to tune in.

References

1. Coudray M, Madhivanan P. Bacterial vaginosis—A brief synopsis of the literature. European Journal of Obstetrics & Gynecology and Reproductive Biology. 2020;245:143-148.

2. Sobel J, Sobel R. Current and emerging pharmacotherapy for recurrent bacterial vaginosis. Expert Opinion on Pharmacotherapy. 2021;22(12):1593-1600.

3. Sanchez S, Garcia P, Thomas K, Catlin M, Holmes K. Intravaginal metronidazole gel versus metronidazole plus nystatin ovules for bacterial vaginosis: A randomized controlled trial. American Journal of Obstetrics and Gynecology. 2004;191(6):1898-1906.

4. Vodstrcil LA, Plummer EL, Fairley CK, et al. Male-Partner Treatment to Prevent Recurrence of Bacterial Vaginosis. N Engl J Med. 2025;392(12):1125-1135. doi:10.1056/NEJMoa2405404.

5. Lennon NJ, Patil S, Crossman DK, et al. The microbiome composition of a man's penis predicts incident bacterial vaginosis in his female partner. Front Cell Infect Microbiol. 2020;10:433. doi:10.3389/fcimb.2020.00433.

6. Mehta S, Zhao D, Green S, Agingu W, Otieno F, Bhaumik R, et al. The Microbiome Composition of a Man's Penis Predicts Incident Bacterial Vaginosis in His Female Sex Partner With High Accuracy. Frontiers in Cellular and Infection Microbiology. 2020;10.

7. Swidsinski A, Doerffel Y, Loening-Baucke V, Swidsinski S, Verstraelen H, Vaneechoutte M, et al. Gardnerella Biofilm Involves Females and Males and Is Transmitted Sexually. Gynecologic and Obstetric Investigation. 2010;70(4):256-263.

8. Lewis F, Bernstein K, Aral S. Vaginal Microbiome and Its Relationship to Behavior, Sexual Health, and Sexually Transmitted Diseases. Obstetrics & Gynecology. 2017;129(4):643-654.

9. Hickey RJ, et al. Characterization of the vaginal microbiota of women of reproductive age. BMC Microbiology. 2012;12:193. https://doi.org/10.1186/1471-2180-12-193

10. McClelland RS, et al. Risk factors for bacterial vaginosis in HIV-1 seronegative women in Nairobi, Kenya. Sexually Transmitted Diseases. 2006;33(8):493-498. https://doi.org/10.1097/01.olq.0000211367.56946.96

11. Sanchez S, Garcia P, Thomas K, Catlin M, Holmes K. Intravaginal metronidazole gel versus metronidazole plus nystatin ovules for bacterial vaginosis: A randomized controlled trial. American Journal of Obstetrics and Gynecology. 2004;191(6):1898-1906.

12. Sobel J, Sobel R. Current and emerging pharmacotherapy for recurrent bacterial vaginosis. Expert Opinion on Pharmacotherapy. 2021;22(12):1593-1600.

13. Coudray M, Madhivanan P. Bacterial vaginosis—A brief synopsis of the literature. European Journal of Obstetrics & Gynecology and Reproductive Biology. 2020;245:143-148.