Expert Q&A | When & Why to Test Your Vaginal Microbiome

We knew that a Q&A with Evvy Senior Scientist Dr. Krystal Thomas-White, PhD, would be interesting, but we weren't expecting to have our minds blown multiple times. A microbiologist and bacteria superfan, Dr. Thomas-White studies the microscopic organisms that camp out in the vaginal canal — and is on a mission to find new solutions for women dealing with infections like bacterial vaginosis (BV) and urinary tract infections (UTIs).

When we recently hopped on a Zoom, she not only explained the science behind Evvy’s vaginal microbiome test, she clarified what we know about the vaginal microbiome and fertility, how perimenopause and menopause can upset the bacterial balance, and why we still know next to nothing about Candida, aka vaginal yeast.

Give our convo a read and you’ll soon be talking about the vaginal microbiome to anyone who will listen.

How did you come to study the vaginal microbiome?

I'm one of those weird people that absolutely love bacteria. I’ve been studying bacteria since undergrad. Then in grad school, I was very fortunate to end up in a lab that was studying microbiomes, which eventually led to studying the vaginal microbiome at Evvy.

Thanks to the research we’ve done at Evvy, we are now able to identify a long list of different types of bacteria and fungi that make up the vaginal microbiome.

There’s a photo of the vaginal microbiome on Evvy’s website that's a little unsettling — there is SO MUCH bacteria!

I completely understand the feeling. We are walking, talking ecosystems, and whole worlds live and die in us every day. We’ve co-evolved with certain strains of bacteria and can't live without them. In fact, humans are the only species in the animal kingdom that has a Lactobacillus-dominant vagina. Why did Lactobacillus choose us? And why did we choose them? There is something about those specific strains that allow for colonization, and no other strains are gonna work. But more research is needed to figure out what that is.

Most of us have grown up thinking that all bacteria are bad, but in reality there are so many bacteria that are beneficial to our health. The bacteria in our gut is the thing that allows us to get nutrients from our food. The bacteria in your vagina is what's helping protect it from invading pathogens. The bacteria in the microbiome are our protectors and they’re there to work with us, and keep us healthy.

I’ve read that disruptions in the vaginal microbiome may impact fertility and even lead to early pregnancy loss. Is this true?

The research on this issue is quite new. One thing we know is that the vaginal microbiome is part of our immune system. And we know that inflammation can be very detrimental to carrying a pregnancy to term or potentially even getting pregnant. The microbiome is able to either trigger an inflammatory response or be anti-inflammatory (basically saying “no, we're all good here”).

So there’s a delicate balance with inflammation and fertility that, again, we're only just now starting to understand. What science has shown is all association-based. For example, studies show if you have a Lactobacillus-dominant microbiome, you're more likely to have a successful IVF cycle, and if you have a more Lactobacillus-dominant during pregnancy, you're less likely to deliver pre-term. More research is needed to help us understand why or how.

Another thing we know — and have known for a long time — is that sperm have sensors for bacteria on them, which is remarkable. A sperm’s only job is to get to the egg, so it has very limited functionality. It has to move. It has to sense where the egg is and get there. Very basic stuff. And yet it has sensors for bacteria.

That means there is an evolutionary benefit for sperm to recognize bacteria in the vaginal microbiome, we’re just not clear on what exactly that benefit is. There are currently lots of researchers trying to figure out that puzzle.

Is there enough information to support testing your vaginal microbiome if you’re struggling with infertility?

I think it’s safe to say that, based on the research we have and the fact that there’s very little risk involved when it comes to taking steps to improve your microbiome, it’s worth trying. You can equate it to doing 23andMe genetic testing to look at your carrier status for genes before getting pregnant. It's information you may want to know as you're preparing for the fertility journey.

For those of us in menopause, what do we know about how estrogen impacts the vaginal microbiome?

We know that estrogen is linked to levels of the protective Lactobacillus bacteria. We know that estrogen increases stores of glycogen in the vaginal lining, which is what Lactobacilli like to eat. And so higher estrogen results in a bloom of Lactobacillus. This is great because these bacteria prevent disruptive microbes from growing in the vagina. They produce lactic acid and other compounds that kill off pathogens and they simply grow to high amounts and don’t leave any space for other bacteria to colonize.

When you lose estrogen, say in menopause or postpartum, your vaginal wall thins, meaning there are fewer cells, which leads to symptoms like dryness and pain with sex. Along with that, the Lactobacilli loses some their food source, and so you just don't get as much lacto around. As a result, you’re less protected from the introduction of pathogens.

Luckily, we know that if you provide topical estrogen back into the system, it's the same as the estrogen that you would be making yourself. Therefore, you get the increase in glycogen and the increase in lactobacilli and all the benefits that go along with it. Topical estrogen has been shown to improve symptoms of dryness and pain and to decrease rates of UTIs in menopausal women. While not having a significant effect on the levels of circulating estrogen (estrogen in the blood stream). In general topical estrogen seems to have positive and powerful effects.

What are some specific scenarios when it’s beneficial to do testing with Evvy?

The Evvy test provides us with a helpful snapshot of an individual's vaginal microbiome. When taken multiple times a year, you can get even more useful information. So if you’re having recurrent infections and the treatments you’ve tried aren’t working, that’s definitely a good time to try Evvy. Many people use Evvy to rule out bacterial infection as a cause of their symptoms. Others have just had their first infection and want to understand what’s happening and why.

We also have a lot of people who are just interested in how their microbiome fluctuates over time. These fluctuations are in response to a number of factors, including your hormones, menstruation, sexual activity, whether you’re under a lot of stress, have taken antibiotics, and so on. By using an Evvy test every couple of months we can get a sense of what’s normal for you.

What’s amazing is that most of these individuals have opted into being included in research and so they’re also contributing to this invaluable science. One of Evvy’s primary goals is to bridge the gender health gap and every Evvy user who opts into research is helping us accomplish that.

I'm curious about the treatments Evvy offers in response to results. How far along is the research in that area?

All of our tests are reviewed by a doctor and then you work with a doctor to figure out what treatment is best for you. For example, the doctors can choose an appropriate antibiotic to attack the types of disruptive bacteria in your results. And then we offer a probiotic to help your microbiome recover from the effects of the antibiotic.

Many other strategies that we recommend at Evvy involve making lifestyle changes that can protect or improve the microbiome. Things as simple as using a condom during sex, or taking steps to manage stress, can be extremely helpful.

Can you explain how probiotics work, especially after you’ve taken an antibiotic?

Antibiotics function like a wildfire that just goes through and completely devastates a forest. If you let that scorched forest be after a fire, sometimes the exact same species of trees will grow back up. But other times, another tree or plant species will come in and take over and all of a sudden you have an entirely different landscape.

With the vaginal microbiome, we don’t want a harmful, invasive species of bacteria to take over after antibiotics have cleared it out. So we use a probiotic to introduce a helpful strain of bacteria to take up space. This prevents harmful bacteria from taking up residence and gives your own healthy bacteria a chance to flourish.

Wait, so the probiotic strain doesn’t take hold. Why not?

It doesn’t. It’s fairly rare for the probiotic strain itself to take hold in the vagina and science is not sure why. Unfortunately, there hasn’t been nearly enough research into the mechanism around probiotics for us to have an answer to that question. But we do know that a probiotic can keep the space nice and open for healthy bacteria.

Part of the issue is that the strains that are available for treatments are not necessarily the exact same strains of lactobacilli that are known to exist in the vagina. There are currently a lot of researchers working on creating the right strain (or combination of strains) that can actually colonize.

When you get tested at the gynecologist for BV, does the test reveal what type of bad bacteria has taken over?

It really depends on the gynecologist. Many don’t test at all. If they see symptoms consistent with bacterial vaginosis (BV), they give you an antibiotic. For those who do test, there are many tests available and most provide very limited information. What we're trying to do is provide a more comprehensive picture.

Have there been any recent insights into vaginal fungi?

Great question. The mycobiome — myco as in yeast — of the vagina is very poorly studied.

We know that Candida is the main genus of yeast that causes infections. And we know there are a lot of people that have Candida without any symptoms at all. But as far as what other fungus is present in the vagina, it’s very hard to study. So that hasn't been as well documented as the bacteria. This is really the gender health gap coming into play.

I want to circle back to probiotics. Are there different probiotics that you give people in different circumstances?

We combine a couple of strains that have been researched the most thoroughly and use a compounding pharmacy to create a high quality probiotic. We also offer suppository probiotics that are very challenging to find outside of Evvy.

Another thing to keep in mind is what might work for one person probiotic-wise may not work for another. And again, we don't quite understand why that is, but it probably has a lot to do with your starting microbiome, and if you're taking it in conjunction with an antibiotic versus on its own.

When you think of what’s on the verge, in terms of research in your field, what are you excited about?

I believe the vaginal microbiome is reaching a tipping point similar to the one that cancer diagnostics reached in the early 2000s. Before that point, there was a lot of effort to “find a cure for cancer.” Since then, thanks to the genomics revolution, we’ve realized that there are hundreds of different types of cancers and every cancer has a different genetic mutation or series of mutations that's causing that cancer. So now we know there are 100s of different types of cancers so there will be 100s of different types of cures.

So now, we categorize the cancers by organ type and mutation which allows us to better target our treatments. We know how to treat certain combinations while others need a lot more research, but at least we can target our research more effectively as well.

Right now, we talk about BV as if it’s one thing, when it really encompasses a lot of very distinct subpopulations. And once we can appropriately diagnose and categorize the different types of BV, then we can start to say, okay, this treatment is going to work for this subtype. I think the same thing is going to be true for urogenital infections overall, like UTIs.

That’s what we’re aiming to achieve with our Evvy data and we’re well on our way.