Apr 12, 2022


Our bodies are beautiful and complex

At this very moment, there are trillions of microorganisms (think bacteria, viruses and fungi) working to help us digest food, produce vitamins and regulate our immune system, among other things. Collectively, these tiny organisms are known as the microbiota. What we know about the human microbiota is that, like a fingerprint, every person has their own unique composition. Many factors play a role in determining what microbiota will live in your body: your genetics, in-utero exposures, your diet, stress levels, environmental factors, and your medication use.[1-2]

Interestingly, the differences between individuals are so wide that we can each be identified by the microbiota signature left on surfaces we touch frequently — for most of us, this is probably our keyboards or phone screen! While there are tons of different microbiota ecosystems (the skin, nose, throat, mouth, gut, and breastmilk to name a few), we’re going to take a deeper look at just one of these ecosystems: the vaginal microbiota.[3-4]

The vaginal microbiota, is not what you expect

With ‘gut health’ gaining popularity, you might be aware that the digestive system is one place where bacteria diversity is encouraged. A healthy vagina, on the other hand, should lack diversity. Specifically, we want the vagina to be dominant in one type of bacteria, a bacteria called lactobacilli. When the vagina is lactobacilli-dominant, it means its pH levels are what they should be. Optimal pH levels in the vagina ensure that infections are fought off, inflammation is kept at bay and reproductive potential is enhanced.[5]

The influence of vaginal microbiota on urinary tract infections (UTIs)

UTIs are one of the most common (and probably most frustrating) bacterial infections around, affecting approximately 150 million people each year. In fact, up to 60% of women will have at least one UTI in their life. When the vagina is lactobacilli-dominant, the low pH levels create a nice healthy acidic environment where common urinary tract pathogens (such as E.coli) cannot grow. Essentially, probiotics like lactobacilli help keep UTIs away. And there’s evidence to support this – an interesting study of women who had experienced at least one UTI in the past 12 months found that the use of vaginal probiotics improved the microorganisms inside the vagina and significantly reduced the chance of further UTIs![6-9]

The influence of vaginal microbiota on fertility

For people who experience difficulty conceiving, restoring a lactobacilli-dominant vaginal microbiota is essential. Why? Because those who are experiencing infertility generally have less lactobacillus and altered vaginal microbiota around ovulation. We also know that the success of fertility treatments, such as in-vitro fertilization (IVF), intracytoplasmic injection (ICSI) and intrauterine insemination (IUI), is significantly reduced when a woman’s vaginal ecosystem is not lactobacilli-dominant.[10-12]

When it comes to pregnancy, too, vaginal microbiota matters. An article published in the International Journal of Genomics found that, compared to healthy pregnancies, 80% of those who experienced miscarriage had significantly lower levels of lactobacillus in the vagina.[13] Similarly, changes in vaginal microbiota and subsequent infections (such as thrush) during pregnancy are associated with poor placental growth, which can increase the risk of preterm birth and other adverse pregnancy outcomes.[14]

Restoring a lactobacilli-dominated vaginal ecosystem

I think we can all agree on just how important a healthy vaginal ecosystem is. Here are some ways you can restore and rebalance your vaginal microbiota –

  • Quit smoking. There’s a clear link between cigarette smoking and altered levels of lactobacilli. Smoking is also thought to increase the possibility of vaginal infections like bacterial vaginosis.[15]
  • Reconsider the use of certain contraceptives. Spermicides, diaphragms and intrauterine devices can alter the vaginal microbiota and place you at greater risk of recurrent thrush, UTIs, and bacterial vaginosis.[16-18]
  • Address nutrient deficiencies. A small but important study published in the British Medical Journal found that deficiencies in magnesium, zinc and vitamin E can alter the vaginal microbiome. This is because nutrient deficiencies led to increased inflammation, poor antioxidant status and, therefore, poor defence against recurrent infections.[19]
  • Consider whether you really need antibiotics. Your microbiota can become quite unstable after completing a round of antibiotics and, because of this instability, unwanted pathogens can reemerge. The problem is that if we continue doing round-after-round of antibiotics, not only can drug resistance and biofilms occur, but the vagina can lose that important lactobacillus-dominance.[20]
  • Get assistance before starting supplementation. There are different strains of Lactobacillus species that are required for a healthy vaginal microbiota. Always avoid self-prescription and visit your naturopath for guidance on what supplements best suit your needs.

A reflection

A person’s vaginal microbiota will vary dramatically throughout their life cycles. And, when the vaginal microbiota is dominated by the Lactobacillus species, we’re likely to see lots of positive health outcomes. Take care, down there.


[1] Cho, I., et al. The Human Microbiome: at the interface of health and disease. Nature Reviews Genetics, 2012. 13(4). PMID: 22411464.

[2] D’Argenio, V., et al. The role of the gut microbiome in the healthy adult status. International Journal of Clinical Chemistry, 2015. PMID: 25584460.

[3] Fierer, N., et al. Forensic identification using skin bacterial communities. Proceedings of the National Academy of Sciences of the United States of America, 2010. 107(14). PMID: 20231444.

[4] Gilbert, J., et al. Current understanding of the human microbiome. Nature Medicine, 2018. 24(4). PMID: 29634682.

[5] Hong, X., et al. The association between vaginal microbiota and female infertility: a systematic review and meta-analysis. Archives of Gynaecology and Obstetrics, 2020. 302(3). PMID: 32638096.

[6] Meštrović, T., et al. The Role of Gut, Vaginal, and Urinary Microbiome in Urinary Tract Infections: From Bench to Bedside. Diagnostics, 2021. 11(1). PMID: 33375202.

[7] Medina, M., et al. An introduction to the epidemiology and burden of urinary tract infections. Therapeutic Advances in Urology, 2019. PMID: 31105774.

[8] Lewis, A.L., et al. Roles of the vagina and the vaginal microbiota in urinary tract infection: evidence from clinical correlations and experimental models. GMS Infectious Diseases, 2020. PMID: 32373427.

[9] Stapleton, A.E., et al. Randomized, placebo-controlled phase 2 trial of a Lactobacillus crispatus probiotic given intravaginally for prevention of recurrent urinary tract infection. Clinical Infectious Diseases, 2011. 52(10). PMID: 21498386.

[10] Zhao, C., et al. Characterization of the Vaginal Microbiome in Women with Infertility and Its Potential Correlation with Hormone Stimulation during In Vitro Fertilization Surgery. mSystems, 2020. 5(4). PMID: 32665329.

[11] Koedooder, R., et al. The vaginal microbiome as a predictor for outcome of in vitro fertilization with or without intracytoplasmic sperm injection: a prospective study. Human Reproduction, 2019. 34(6). PMID: 31119299.

[12] Amato, V., et al. Differential Composition of Vaginal Microbiome, but Not of Seminal Microbiome, Is Associated With Successful Intrauterine Insemination in Couples With Idiopathic Infertility: A Prospective Observational Study. Open Forum Infectious Diseases, 2019. 7(1). PMID: 31915713.

[13] Xu, L., et al. Vaginal Microbiota Diversity of Patients with Embryonic Miscarriage by Using 16S rDNA High-Throughput Sequencing. International Journal of Genomics, 2020. PMID: 33299847.

[14] Dong, Z., et al. Vaginal Exposure to Candida albicans During Early Gestation Results in Adverse Pregnancy Outcomes via Inhibiting Placental Development. Frontiers in Microbiology, 2021. PMID: 35281308.

[15] Brotman, R.M., et al. Association between cigarette smoking and the vaginal microbiota: a pilot study. BMC Infectious Diseases, 2014. PMID: 25169082.

[16] Stapleton, A.E. The Vaginal Microbiota and Urinary Tract Infection. Microbiology Spectrum, 2016. 4(6). PMID: 28087949.

[17] Hooton, T.M., et al. Association between bacterial vaginosis and acute cystitis in women using diaphragms. Archives of Internal Medicine, 2989. 149(9). PMID: 2673116.

[18] Achilles, S.L., et al. Impact of contraceptive initiation on vaginal microbiota. American Journal of Obstetrics and Gynecology, 2018. 218(6). PMID: 29505773.

[19] Tuddenham, S.A., et al. O13.5 Association between dietary intake and dysbiotic vaginal microbiota. Sexually Transmitted Infections, 2015.

[20] Mayer, B.T., et al. Rapid and Profound Shifts in the Vaginal Microbiota Following Antibiotic Treatment for Bacterial Vaginosis. The Journal of Infectious Diseases, 2015. 212(5). PMID: 25676470.





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