Beyond the Gut: How The Vaginal Microbiome Impacts Fertility, Immunity, and Wellness

Prof. Melissa Mezzari

Melissa Paola Mezzari, Ph.D.

Director of Microbiome Innovation - YON E Health

You have probably heard about the human microbiome, which is defined by the trillions of microbial cells that colonize the human body. When people discuss it, the conversation tends to focus on the gut microbiome and its impact on digestion, mood, and overall health. But there is another similarly critical microbiome in our female body that is often overlooked, and it deserves just as much attention: the vaginal microbiome. Think of it as a “forgotten organ” that quietly but powerfully influences your immunity, fertility, and everyday well-being.

Although much smaller than the gut microbiome, this microbial ecosystem is anything but simple. It fluctuates with your monthly cycle, shifts during pregnancy, and changes after menopause. Understanding this dynamic environment that shifts with your life stages, from menstruation to pregnancy and menopause, could reshape how we think about women’s health. 

Good Bacteria, But More Specifically the Right Kind

We know “good” bacteria like Lactobacillus are essential for maintaining a healthy vaginal environment, but not all Lactobacillus gives the same level of protection. According to a 2020 study by Chee et al., although Lactobacillus crispatus produces strong acids to protect from harmful pathogens, others like Lactobacillus iners are not able to create a strong defense against them. That said, this is not just about the presence of good bacteria; it’s about having the right microbial composition to support a healthy and balanced vaginal microbiome. 

This Microbiome Might Predict Your Fertility

If you’re planning to start a family, the composition of your vaginal microbiome could play a significant role in your fertility story. A 2022 study by Hong et al. indicate an association between higher levels of Lactobacillus gasseri and increased rates of conception, while those dominated by Lactobacillus iners might face challenges. Additionally, a research from Chee et al. (2020) has observed the presence of an imbalanced microbiome associated with a higher risk of pregnancy loss and preterm labor. The emerging vaginal microbiome science offers potential biological explanations for fertility and pregnancy health, highlighting a new area of focus for women hoping to conceive.

Your Body’s Invisible Defender

The vaginal microbiome goes far beyond a hospitable environment for conception. It is a unique community of bacteria that acts as a frontline immune defense against a wide range of pathogens. 

According to Kalantar-Zadeh et al. (2024), good Lactobacillus species produce antimicrobial compounds, including lactic acid and proteins, that keep harmful bacteria and infections at bay. When the balance tips, infections from bacterial vaginosis to HPV can become more likely, and fertility can also take a hit.

Menopause Changes Everything

While the gut microbiome stays relatively steady with age, the vaginal microbiome undergoes big changes during menopause. A 2021 study by Yoshikata et al. compared the gut and vaginal microbiomes of pre- and postmenopausal women and found the difference to be profound. They observed that protective bacteria can drop dramatically, from an average of 70% in premenopausal women to just 10% in postmenopausal women. This sharp drop is directly linked to lower estrogen levels, thus leaving postmenopausal women more vulnerable to infections. This is a stark reminder that this microbial ecosystem is deeply tied to our hormones and life stages.

The Crosstalk Between Them

Scientists are discovering a fascinating “gut-vagina axis,” meaning your gut health might actually influence what happens in your vaginal microbiome, and vice versa. The 2021 study by Yoshikata et al. was one of the first to uncover this connection or “crosstalk”, where certain bacteria appear in both places, working together in ways that we are just beginning to understand. It’s a whole new lens on women’s health, where a fascinating new frontier of the microbial world connections within our bodies are just getting started. 

What’s Next? A Future Tailored Just for You

The vaginal microbiome is an emerging science that is proving to be a powerful and precise indicator of health and fertility, with the potential to personalize care like never before. At YON E Health, we envision a future where doctors can tailor treatments based on a woman’s unique bacterial composition. It is a big step forward from one-size-fits-all approaches.

Imagine being able to proactively shape your vaginal ecosystem for better health, all grounded in science and personalized care. The “forgotten organ” is finally getting the attention it deserves, and the possibilities for advanced women’s health are just getting started.

References

1. Chee, W. J. Y., Chew, S. Y., & Than, L. T. L. (2020). Vaginal microbiota and the potential of Lactobacillus derivatives in maintaining vaginal health. Microbial cell factories, 19(1), 203. https://doi.org/10.1186/s12934-020-01464-4 
2. Hong, X., Zhao, J., Yin, J., Zhao, F., Wang, W., Ding, X., … & Wang, B. (2022). The association between the pre-pregnancy vaginal microbiome and time-to-pregnancy: a Chinese pregnancy-planning cohort study. BMC medicine, 20(1), 246. https://doi.org/10.1186/s12916-022-02437-7 
3. Kalantar-Zadeh, K., Susic, D., & Hyett, J. (2024). Vaginal Sensors. ACS Sensors, 9, 3810–3827. https://doi.org/10.1021/acssensors.4c00567 
4. Yoshikata, R., Yamaguchi, M., Mase, Y., Tatsuzuki, A., Myint, K. Z. Y., & Ohta, H. (2022). Age-related changes, influencing factors, and crosstalk between vaginal and gut microbiota: a cross-sectional comparative study of pre-and postmenopausal women. Journal of Women’s Health, 31(12), 1763-1772. https://doi.org/10.1089/jwh.2022.0114

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