What Is the Vaginal Microbiome?

The vaginal microbiome is the complex ecosystem of microorganisms, including bacteria and fungi, that live inside the vagina (aka the vaginal microbiota or vaginal flora). Although you may have never heard of the vaginal microbiome, it plays a major role in your reproductive — and overall — health.

Vaginal discomfort is one of the leading reasons women seek healthcare advice, and over 90% of these cases can be attributed to imbalances in the vaginal microbiome. Imbalances in the vaginal microbiome can manifest as yeast infections, bacterial vaginosis (BV), cytolytic vaginosis (CV), aerobic vaginitis (AV), and more.

But your vaginal microbiome affects far more than just your vaginal health. An imbalanced vaginal microbiome is also associated with infertility, pregnancy complications, sexually transmitted infections (STIs), and possibly even cancer. So, why is it still such a mystery?

Microbiome research is a fascinating field that's evolving quickly. While scientists have been working for decades to decipher the microbiomes of different parts of our bodies (like our gut and skin), the vaginal microbiome hasn't received as much attention as it deserves — you can blame the gender health gap for that. But that’s why we’re here!

Keep reading to learn how the vaginal microbiome works, what can throw it off, how to balance your vaginal microbiome, and how it could affect your reproductive health (plus how an at-home vaginal microbiome test can help).

Key takeaways

• The vaginal microbiome (also called vaginal flora) is the community of bacteria and fungi in your vagina, and a healthy one is usually dominated by Lactobacillus.
• An imbalance happens when Lactobacilli drop and other bacteria take over, often after antibiotics, hormonal shifts, sex, douching, or smoking.
• Signs can include unusual discharge, odor, or itching, though many women have no symptoms.
• Balancing it starts with treating any infection, then cutting common disruptors.

How does the vaginal microbiome work?

Your vaginal flora includes many different species of bacteria, fungi, viruses, and more, but one species plays a critical role in its health: Lactobacillus bacteria, or Lactobacilli, often referred to as the “good” or “protective” bacteria. 

Lactobacilli are the MVPs of the vaginal microbiome and play a crucial role in keeping your vagina safe and healthy. They do this in a few different ways:

• Produce lactic acid to maintain a low vaginal pH (between 3.8-4.5), which helps protect your vagina microbiome against harmful pathogens. 
• Take up space on the vaginal wall to prevent other harmful bacteria from sticking around.
• Produce bacteriocins (your body's natural antibiotic) to stop disruptive bacteria from growing.
• Can help reduce inflammation in your genital area. 

When there aren't enough protective bacteria like Lactobacilli in your vaginal microbiome, disruptive bacteria like Gardnerella, E.coli, and Mycoplasma can take over and cause vaginal dysbiosis. Vaginal dysbiosis is an umbrella term for an imbalance in the vaginal microbiome. 

Vaginal dysbiosis can cause infections like bacterial vaginosis, yeast infections, urinary tract infections (UTIs), and more, leading to unwanted symptoms like itching, burning, irritation, and unusual vaginal discharge.

Vaginal infections and the microbiome

The most common type of vaginal dysbiosis is an infection called bacterial vaginosis (BV), which is clinically defined as an overgrowth of disruptive bacteria in the vaginal microbiome. This often happens when beneficial bacteria are depleted, and pathogenic bacteria overtake the microbiome.

One in three women will get bacterial vaginosis each year, and up to 84% of these cases are asymptomatic. BV disproportionately affects Black and Hispanic women, with disappointingly lacking research as to why (that's one of the many things Evvy's here to change!). 

But BV isn’t the only infection of the vaginal microbiome — there are many other forms of vaginal dysbiosis, such as yeast infections, aerobic vaginitis (AV), and cytolytic vaginosis (CV), which can have frustrating — and confusingly similar — symptoms, such as itchiness, abnormal discharge, and burning.

If you're here because you're dealing with recurring vaginal infections, just know that you're not alone. Bacterial vaginosis is the most common cause of vaginal symptoms among women, and at any given time, 1 in 3 women are dealing with bacterial vaginosis. 1 in 3 women will have a UTI by the time they're 24, and half will experience one at some point. And that's not all — a whopping 75% of women will experience a yeast infection at least once in their lifetime. 

Despite vaginal discomfort being one of the leading reasons why women and people with vaginas seek healthcare in the U.S., misdiagnosis and recurrence rates are high (over 50% for both!).

That's why Evvy built the world’s first and only metagenomic vaginal microbiome test and personalized clinical care: so we can provide more accessible and effective care for anyone with a vagina. While we're at it, we are also (finally) doing the research to better understand and treat these conditions.

The impact of the vaginal microbiome on overall health

It turns out the composition of the vaginal microbiome doesn’t just affect vaginal infections and symptoms — it plays a crucial role in female health, and emerging research has uncovered groundbreaking insights into how it affects our overall well-being (beyond the vagina).

Research has shown that having a disrupted vaginal microbiome can create a favorable environment for infectious microorganisms to enter, increase inflammation, and inhibit your immune response within the reproductive tract, affecting the rest of your reproductive organs.

When protective bacteria dominate the vaginal microbiome, it can make it harder for disruptive microbes to thrive, keeping the immune barrier of your reproductive tract strong and healthy.

Research has shown that having a disrupted vs. healthy vaginal microbiome is associated with differing outcomes across:

• Contracting STIs such as chlamydia, gonorrhea, trichomoniasis, herpes, HPV, and HIV
• Pelvic inflammatory disease (PID)
• Fertility issues or failed IVF cycles 
• Pregnancy complications such as miscarriage, preterm birth, neonatal problems, and preeclampsia
• Gynecological cancers such as ovarian, cervical, or endometrial cancer
• Cervicitis (inflammation of the cervix)
• Toxic shock syndrome (TSS). 

By learning the composition of your unique vaginal microbiome, you can uncover how to proactively support its protective function and take a proactive approach to your long-term health.

What causes an imbalanced vaginal microbiome? 

An imbalance happens when protective Lactobacilli drop, and other bacteria or yeast take over. Some shifts, like those that happen during your period, are normal and short-lived, and your microbiome usually bounces back on its own.

Your vaginal microbiome shifts with your behaviors, hormones, and more. There are many reasons that the vaginal microbiome can change, but some common ones include:

• Sex (especially new partners or multiple partners), which can introduce new bacteria
• Being pregnant or postpartum
• Going through menopause, when lower estrogen means less fuel for Lactobacilli
• Changing birth control method
• Menstrual blood in the vagina
• Cyclical hormonal fluctuations
• Taking certain medications/supplements (especially antibiotics), which can wipe out good bacteria along with the bad
• Smoking, which is linked to fewer Lactobacilli
• Stress
• Using feminine hygiene products (especially douches), which can wash away protective bacteria. 

Signs your vaginal microbiome is out of balance 

Plenty of people with an imbalanced vaginal microbiome don’t notice anything at all (remember, up to 84% of BV cases have no symptoms). When it does cause symptoms, the most common ones are:

• Unusual vaginal discharge
• A fishy or strong odor
• Itching, burning, or irritation
• Burning when you pee

Because BV, yeast infections, AV, and CV can all look alike, testing is the best way to find out what’s actually going on.

How to balance your vaginal microbiome

There’s no single quick fix for an imbalanced vaginal microbiome. Balancing it means helping Lactobacilli become the dominant bacteria again, and that takes time. If you have an active infection like BV or a yeast infection, the first step is getting it treated by a provider, since lifestyle changes alone won’t clear it. From there, cutting back on the disruptors above can help keep things steady.

Not sure where you stand? A vaginal microbiome test can show which bacteria are dominating your microbiome right now (more on that in the CST section below), and a provider can confirm any diagnosis.

Everyday habits that support healthy vaginal flora

A few small changes can make it easier for protective bacteria to thrive:

• Skip douching and scented washes: Your vagina cleans itself, and these products can wash away the good bacteria.
• Practice safe sex: Consistent condom use has been linked to more L. crispatus, one of the most protective bacteria. 
• Don’t smoke: Smokers tend to have fewer Lactobacilli than nonsmokers.
• Only take antibiotics when they’re prescribed: Antibiotic treatment can clear out protective bacteria along with harmful ones.

Diet and the vaginal microbiome: What the research shows

The research on diet and the vaginal microbiome is still young, and most of it is observational (meaning it shows links, not cause and effect). One study found that eating more fat was linked to more BV, while more folate, vitamin E, and calcium were linked to less severe BV. A high-glycemic-load diet (lots of foods that spike your blood sugar) has also been linked to BV. No single food will rebalance your microbiome, but some foods may help support it.

Not all vaginal microbiomes are the same

Just as there are different blood types, research has shown that most vaginal microbiomes fall into one of five general categories known as "Community State Types” (CSTs). 

There are 5 general categories of CSTs, and the Community State Type is determined by which microbes are most dominant in your microbiome, and research has shown differences in symptoms, infections, and health outcomes across the CSTs. But the good news is that unlike blood types, you can switch from one CST to another as your microbiome shifts. 

Of the five CSTs, four of them are dominated by a specific species of Lactobacilli: 

• Type 1: ‍Lactobacillus crispatus 
• Type 2: ‍Lactobacillus gasseri 
• Type 3: ‍Lactobacillus iners 
• ‍Type 5: Lactobacillus jensenii 

You're classified as Type 4 if you don't have a dominant Lactobacillus species. This group includes people experiencing vaginal infections but can also include some healthy vaginal microbiome compositions. That's why Type 4 is divided into five more subgroups. Want the deep dive? You can learn more in our comprehensive article on Community State Types.

Want to know your vaginal microbiome CST?

With the Evvy Vaginal Microbiome Test, you can identify the bacteria and fungi in your microbiome and which CST your microbiome falls into right now. Although the research on these types is always improving, vaginal microbiome testing can provide insight into your individual microbial composition, both now and as it changes over time with your behaviors. Our team uses the most comprehensive data and advanced testing methods to help you understand what your type means for your health and what you can do to improve it. Results are intended to screen for bacteria and fungi, and a provider confirms any diagnosis.

FAQs

What does a vaginal microbiome test do?

A vaginal microbiome test identifies the bacteria and fungi in your vagina that can contribute to symptoms like itching, odor, and discharge, as well as infections like bacterial vaginosis (BV), yeast infections, UTIs, and more. Evvy’s at-home vaginal microbiome test is the first-ever CLIA/CAP certified, metagenomic vaginal microbiome test. It’s a simple, at-home swab designed to screen for bacteria and fungi in your vaginal microbiome, and a provider confirms any diagnosis. Your vaginal microbiome is constantly changing, so testing regularly can help you spot shifts early. And when you change your routine (like trying a new probiotic or birth control), testing over time with an Evvy Membership shows how it affects your microbiome.

What is the best probiotic for vaginal health? 

Look for one with vaginal Lactobacillus species, like L. crispatus, whether it’s an oral capsule or a vaginal probiotic you insert directly. Evvy Women’s Complete Probiotic offers 3-in-1 microbiome support for gut, urinary, and vaginal health. Just remember that probiotics don’t replace treatment for an active infection.

Can your gut health affect your vaginal microbiome?

It may. Your gut microbiome can act as a reservoir for bacteria that disrupt your vaginal flora, which is one reason the two are so closely connected through what’s called the gut-vagina axis. That said, research on exactly how much your gut affects your vagina is still limited.

What does altered vaginal microbiota mean?

Altered vaginal microbiota means the usual Lactobacillus dominance has shifted toward other bacteria. It’s another way of describing vaginal dysbiosis, and it can show up on lab reports. It isn’t a diagnosis on its own, so check in with your provider about what it means for you.