PCOS, BV and the vaginal microbiome

A cute bacteria is covered in little bumps - cysts or follicles from PCOS.

Polycystic ovarian syndrome (PCOS) is one of the most commonly diagnosed conditions in premenopausal women. The main features of PCOS are excess androgen production by the ovaries, lack of ovulation, infertility and insulin resistance​1​.

PCOS is also linked with menstrual disorders, infertility, excess hair growth (hirsutism), acne, weight management and metabolic disturbances​1​, with far-reaching impacts beyond irregular periods and into advancing age​2​.

Research shows changes to the gut and vaginal microbiome in women with PCOS, with differences compared to those without PCOS. Studies suggest changes in microbial diversity and possible dysbiosis (microbial imbalances).​3​

Low-grade chronic inflammation can occur due to microbiome disturbances, particularly when excess in certain bacterial species contributes to metabolic disorders​2,4​.

The vaginal microbiome and its relationship to PCOS symptoms is not well understood, but some studies show reductions in Lactobacillus species, particularly L. crispatus, and increases in Prevotella and other atypical pathogens (Mycoplasma, Chlamydia)​5​.

Pathogen growth is favoured, promoting the growth of bacterial vaginosis (BV)-causing microbes such as Gardnerella vaginalis​6​.

In a study​7​ on the vaginal microbiome and women with PCOS, BV was suspected in 64% of the PCOS group, with an increase in G. vaginalis found in 57%. The researchers suggested a higher rate of BV in PCOS patients than the general population.

Studies on the gut, oral cavity and vaginal microbiome in women with PCOS indicate an increased propensity to experience inflammation, thus destabilisation of the environment​8,9​. High triglycerides, fasting glucose and insulin levels, and metabolic disturbances impact the microbiome​10–12​.

Achieving a balance microbiome by controlling the various imbalances inherent in PCOS is important for management of inflammation and the dysbiotic microbiomes, while also working from the microbiome backwards. It is well observed that the gut microbiome impacts sex hormones​13​.

When the vaginal microbiome is disrupted and there is systematic inflammation, IL-8 and tumour necrosis factor alpha are increased, impacting the hypothalamic-pituitary-ovarian axis (HPA axis) via blood and lymph​5,14,15​.

Interruptions to the normal levels of oestrogen and progesterone due to irregular cycles affect the vaginal epithelial lining of the vagina and reproductive tract, which plays an important role in the vaginal microbiome​3​.

Androgens have been demonstrated to affect the gut microbiome in women with PCOS and androgen excess​13,16,17​. Women with high testosterone have higher gut microbiome diversity, more G. vaginalis, and numbers of lactobacilli​2,3,6​. The length of menstrual cycles impacts lactobacilli levels​5,10​, resulting in greater access by disruptive microbes.


  1. 1.
    Norman RJ, Dewailly D, Legro RS, Hickey TE. Polycystic ovary syndrome. The Lancet. Published online August 2007:685-697. doi:10.1016/s0140-6736(07)61345-2
  2. 2.
    Giampaolino P, Foreste V, Di Filippo C, et al. Microbiome and PCOS: State-of-Art and Future Aspects. IJMS. Published online February 19, 2021:2048. doi:10.3390/ijms22042048
  3. 3.
    Gu Y, Zhou G, Zhou F, et al. Gut and Vaginal Microbiomes in PCOS: Implications for Women’s Health. Front Endocrinol. Published online February 23, 2022. doi:10.3389/fendo.2022.808508
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    Yurtdaş G, Akdevelioğlu Y. A New Approach to Polycystic Ovary Syndrome: The Gut Microbiota. Journal of the American College of Nutrition. Published online September 12, 2019:371-382. doi:10.1080/07315724.2019.1657515
  5. 5.
    Hong X, Qin P, Yin J, et al. Clinical Manifestations of Polycystic Ovary Syndrome and Associations With the Vaginal Microbiome: A Cross-Sectional Based Exploratory Study. Front Endocrinol. Published online April 23, 2021. doi:10.3389/fendo.2021.662725
  6. 6.
    Tu Y, Zheng G, Ding G, et al. Comparative Analysis of Lower Genital Tract Microbiome Between PCOS and Healthy Women. Front Physiol. Published online September 8, 2020. doi:10.3389/fphys.2020.01108
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    Chudzicka-Strugała I, Gołębiewska I, Banaszewska B, et al. Bacterial Vaginosis (BV) and Vaginal Microbiome Disorders in Women Suffering from Polycystic Ovary Syndrome (PCOS). Diagnostics. Published online February 12, 2024:404. doi:10.3390/diagnostics14040404
  8. 8.
    Redelinghuys MJ, Geldenhuys J, Jung H, Kock MM. Bacterial Vaginosis: Current Diagnostic Avenues and Future Opportunities. Front Cell Infect Microbiol. Published online August 11, 2020. doi:10.3389/fcimb.2020.00354
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    Liu R, Zhang C, Shi Y, et al. Dysbiosis of Gut Microbiota Associated with Clinical Parameters in Polycystic Ovary Syndrome. Front Microbiol. Published online February 28, 2017. doi:10.3389/fmicb.2017.00324
  10. 10.
    Lu C, Wang H, Yang J, et al. Changes in Vaginal Microbiome Diversity in Women With Polycystic Ovary Syndrome. Front Cell Infect Microbiol. Published online November 3, 2021. doi:10.3389/fcimb.2021.755741
  11. 11.
    Li N, Li Y, Qian C, et al. Dysbiosis of the Saliva Microbiome in Patients With Polycystic Ovary Syndrome. Front Cell Infect Microbiol. Published online February 16, 2021. doi:10.3389/fcimb.2020.624504
  12. 12.
    Pessione E. Lactic acid bacteria contribution to gut microbiota complexity: lights and shadows. Front Cell Inf Microbio. Published online 2012. doi:10.3389/fcimb.2012.00086
  13. 13.
    Thackray VG. Sex, Microbes, and Polycystic Ovary Syndrome. Trends in Endocrinology & Metabolism. Published online January 2019:54-65. doi:10.1016/j.tem.2018.11.001
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    Duleba AJ, Dokras A. Is PCOS an inflammatory process? Fertility and Sterility. Published online January 2012:7-12. doi:10.1016/j.fertnstert.2011.11.023
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    Parsamanesh N, Moossavi M, Bahrami A, Butler AE, Sahebkar A. Therapeutic potential of curcumin in diabetic complications. Pharmacological Research. Published online October 2018:181-193. doi:10.1016/j.phrs.2018.09.012
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    Torres PJ, Siakowska M, Banaszewska B, et al. Gut Microbial Diversity in Women With Polycystic Ovary Syndrome Correlates With Hyperandrogenism. The Journal of Clinical Endocrinology & Metabolism. Published online January 23, 2018:1502-1511. doi:10.1210/jc.2017-02153
  17. 17.
    Rizk MG, Thackray VG. Intersection of Polycystic Ovary Syndrome and the Gut Microbiome. Journal of the Endocrine Society. Published online November 16, 2020. doi:10.1210/jendso/bvaa177

Jessica Lloyd - Vulvovaginal Specialist Naturopathic Practitioner, BHSc(N)

Jessica is a degree-qualified naturopath (BHSc) specialising in vulvovaginal health and disease, based in Melbourne, Australia.

Jessica is the owner and lead naturopath of My Vagina, and is a member of the:

  • International Society for the Study of Vulvovaginal Disease (ISSVD)
  • International Society for the Study of Women's Sexual Health (ISSWSH)
  • National Vulvodynia Association (NVA) Australia
  • New Zealand Vulvovaginal Society (ANZVS)
  • Australian Traditional Medicine Society (ATMS)