By Gabrielle Gleeson-Solomon, CEO of Tota
Scientific Review by Dr Nick Parkinson, PhD
Shinning a light on the educational gap around the vaginal microbiome.
The vaginal microbiome isn't new. But our understanding of it is.
Most of us grew up learning about periods, contraception, pregnancy and STIs. Almost none of us were told that the vagina comes with its own built-in defence system, helping to keep harmful bacteria in check.
Back in 1892, a German gynaecologist called Albert Döderlein looked at samples from healthy women and found the same type of bacteria time and time again. What’s now known as Lactobacillus. He worked out these bacteria were making the vagina slightly acidic, and that acidity was helping to keep harmful bacteria out.
He was right. We still teach that today.
And then the science barely moved. Women's health has always been under-researched, and the vagina was no exception. For over a century it was filed away as simple, one group of bacteria doing one job. It took DNA sequencing, in the last 15 years, to show that Döderlein's bacteria were only one part of something much bigger: a whole ecosystem of microorganisms living in the vagina.
That ecosystem turns out to matter for a lot more than the odd bout of thrush. Including fertility.
What the vaginal microbiome actually is
The vaginal microbiome is the community of bacteria, fungi and other microorganisms living in the vagina. Billions of them.
"Bacteria" tends to make people think of illness, but most of these aren't harmful at all. Plenty are working for you, protecting the space and making it harder for less welcome microbes to move in. It's the same idea as the good bacteria in your gut that everyone's talking about. A healthy vagina is a busy, balanced ecosystem.
Lactobacillus still does much of the heavy lifting, exactly as Döderlein discovered back in 1892, and there isn't one single species that means healthy. Several different Lactobacillus species can each dominate a healthy vagina, most commonly L. crispatus, L. gasseri, L. jensenii and L. iners. What he couldn't see was everything else in there alongside the Lactobacillus, and how much the balance between them matters.
No two vaginal microbiomes are the same
Just as no two people are identical, no two microbiomes are either. Lactobacillus leads the way in most healthy vaginas, but the exact line-up shifts from woman to woman. There's no single perfect vaginal microbiome or exact definition of a healthy one.
Vaginal microbiomes change over time too. Menstrual cycles, hormones, sex, antibiotics, pregnancy, menopause and plain old illness can all shift the balance of microbes, changing which ones become more or less dominant over time. That's completely normal. The microbiome is surprisingly tough, and most of the time it rights itself without any intervention at all - it really is a built-in defence system!
When your vaginal microbiome becomes unbalanced
However, sometimes the vaginal microbiome can't get itself back to where it was. If the Lactobacillus bacteria drop off and other microbes manage to take over, it can create a suboptimal environment.
When the protective bacteria don't bounce back, there's more room for less welcome bacteria and yeast to grow. That can mean bacterial vaginosis (BV), thrush, and for some women UTIs that keep returning.
And symptoms don't always tell the full story either. Two women with the same symptoms can have completely different microbiomes behind them, and plenty of women whose Lactobacillus has dropped off feel perfectly fine.
So a suboptimal vaginal microbiome can be causing trouble in the background, without any obvious signs. That's part of why it's worth knowing what's actually in there rather than waiting for symptoms to appear.
And it turns out this matters for more than just the typical infections like BV and thrush. Some of the most interesting research right now is looking at what the vaginal microbiome means for fertility and pregnancy.
Can your vaginal microbiome affect fertility?
This is the part we find really interesting and where the research is moving fastest.
The vaginal microbiome doesn't stop at vaginal health. The vagina sits directly below the cervix and the womb, so the balance of microbes in the vagina may influence the rest of the reproductive system. Researchers are increasingly exploring the relationship between vaginal bacteria and fertility, including how the vaginal microbiome might influence embryo implantation and pregnancy.
Researchers are also investigating the relationship between vaginal dysbiosis (BV) and implantation, with several IVF studies suggesting that women with disrupted vaginal microbiomes have lower implantation rates. One of the biggest questions researchers are exploring is: can BV affect fertility? BV is getting particular attention because a growing body of research shows that plenty of women with BV have no symptoms at all, so a disrupted microbiome can be sitting there unnoticed while fertility journeys and treatment goes ahead.
It's worth being clear that this is early science and the research is still ongoing. For now these are associations rather than proven causes, and a microbiome test cannot predict or promise a pregnancy. What a fertility microbiome test can do is show you what's actually there, so anything unusual can be identified early and discussed with your doctor or clinic, rather than after months of trying or the cost of a treatment cycle.
Why most women don’t (yet) know about the vaginal microbiome
The honest answer is that this science is very new. The tools to see the vaginal microbiome properly have only existed for about fifteen years, mostly within academic research settings. Most of what we know about the vaginal microbiome has been discovered since then. It's a rapidly evolving and exciting field, with new discoveries continuing to shape our understanding of the vaginal microbiome.
Even medical training, guidelines and everyday testing are working hard to catch up. Plenty of doctors were never taught any of this in med school because it wasn't in the textbooks when they trained.
Add to that a century of the vagina being treated as simple and women's health being under-researched, and it's not hard to see how something this important went unmentioned.
We think it's about time this was common knowledge
The science now exists to show women what's actually going on in their own bodies. Not just when something goes wrong, but what's normal for them, how it changes over time, and what may be contributing to the symptoms that keep coming back.
That shouldn't be specialist knowledge. It should be something every woman gets told.
We’re on a mission at Tota to give women the information they deserve about their bodies.
Sources
- Ventolini G. Progresses in vaginal microflora physiology and implications for bacterial vaginosis and candidiasis. Womens Health. 2016;12:283-291. PubMed: 27215488
- Dubé-Zinatelli E, Cappelletti L, Ismail N. Vaginal microbiome: environmental, biological, and racial influences on gynecological health across the lifespan. Am J Reprod Immunol. 2024;92(6):e70026. PubMed: 39670915
- Skafte-Holm A, Humaidan P, Bernabeu A, Lledo B, Jensen JS, Haahr T. The Association between Vaginal Dysbiosis and Reproductive Outcomes in Sub-Fertile Women Undergoing IVF-Treatment: A Systematic PRISMA Review and Meta-Analysis. Pathogens. 2021 Mar 4;10(3):295. PubMed: 33806442
This article is for general information and does not replace medical advice. If you're experiencing new, severe, persistent or worsening symptoms, please speak to a GP or another qualified healthcare professional.
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