Maybe you’ve gotten a recent diagnosis from your doctor. Maybe you’re dealing with recurrent vaginal infections. Maybe you’re just curious about what’s up down there. Whatever you’re here to learn, Evvy’s got answers. 

Looking for something we didn’t cover here? Let us know at or with #AskEvvy on social. 

Oh, and let us say one more thing before we get into it: you’re not alone. We know too well that common types of vaginal infections like BV, yeast, UTIs and more can sometimes bring on feelings of frustration, fear, or even shame — but they shouldn’t. Taking care of your health is a normal part of being human — and we’re here to help. 

What is bacterial vaginosis (BV)? ‍

Bacterial vaginosis (BV) is a vaginal infection caused by the overgrowth of disruptive bacteria in your vaginal microbiome. 

A healthy vaginal microbiome is made up mostly of protective bacteria such as lactobacilli, a lactic-acid-producing bacteria that fight pathogens and keep infections away. When lactobacilli dominance is disrupted, your vaginal pH can go up, allowing other types of bacteria to grow and cause an imbalance (known in medicine as dysbiosis). This causes symptoms like discomfort, itching, and abnormal vaginal discharge. ‍

If you’re dealing with BV, you’re far from alone. According to the Center for Disease Control (CDC), BV is the most common vaginal condition in women ages 15-44. and almost 30% of people with vaginas get BV each year.

BV symptoms 

The most common symptoms of BV are a strong, unpleasant, or fishy vaginal odor and unusual vaginal discharge. BV discharge looks thin and watery and is usually white or gray. 

Pain, discomfort, or itchiness, both in general or specifically with sex or peeing, can also be symptoms of BV. However, up to 84% of people with BV may not experience anything at all. 

Bacterial Vaginosis (BV) Symptoms infographic: fishy odor, gray discharge

What causes BV?

‍Here’s a frustrating tidbit from the CDC: “Researchers do not know the cause of BV or how some women get it.” 

If you’re shocked that this is the best available answer for a condition that affects one in three women, you’re not alone. This is why Evvy exists! The vaginal microbiome and BV are massively understudied, and it’s time women and people with vaginas got the research and care they deserve. ‍

However, there is research showing that certain activities or events may increase or decrease your risk of BV. This includes:

The connection between BV and sex

BV is not a sexually transmitted infection (STI) and you can develop BV without ever having sex. Because BV is broadly defined as an imbalance in your vaginal microbiome, you can’t “get” BV from having sex with someone. That said, sex itself (or really putting anything in or near your vagina) can introduce new bacteria and/or change the vaginal pH, allowing opportunistic bacteria to overgrow and cause BV.  

Semen, saliva, or another vaginal microbiome can all disrupt your vaginal flora. This means that having unprotected sex, sex with a new partner, or sex with someone else with a vagina can increase your odds of developing BV.

Hormones and BV 

Hormones play a role in the composition of the vaginal microbiome. Estrogen, in particular, is an important variable in the health of your lactobacilli, the bacteria that create a lactic acid dominant environment in the vagina. Anything that changes estrogen levels can affect the vaginal microbiome. 

This means that it’s important to pay extra attention to your vaginal microbiome anytime your hormones fluctuate: starting with your menstrual cycle, becoming pregnant, going through menopause, and going on or changing birth control method.

Recurrent symptoms? Meet Evvy's at-home vaginal microbiome test, approved by leading OB-GYNs.
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What are the risks associated with BV?

The bacteria present in your vaginal microbiome influence the risk of a variety of other health issues, and untreated BV is associated with: 

What’s the difference between BV and a yeast infection? ‍

BV is not the same thing as having a yeast infection, which is caused by candida (yeast). The main underlying difference is that yeast infections are caused by an overgrowth of Candida, while BV is caused by an overgrowth of a variety of bacteria like Gardnerella

Though the symptoms in these two vaginal infections may overlap, yeast infections are typically characterized by a specific type of vaginal discharge (often compared to cottage cheese) and itchiness, while BV is mostly associated with a fishy odor and thin white or gray discharge.‍

How is BV diagnosed? ‍

BV is typically diagnosed in two ways. The first is symptomatically, based on something called the Amsel criteria. An Amsel criteria diagnosis is when you have 3 of the 4 following symptoms: white discharge, clue cells, a pH over 4.5, and a fishy odor. 

The more specific way to diagnose BV is with a Nugent score. Using the Nugent score, a vaginal smear is examined under a microscope for three bacteria morphotypes: Lactobacillus, Gardnerella, and curved gram rods.  

A score is then created based on how many of each type have been counted, essentially looking for low, intermediate, or high diversity of bacteria in the sample. A score under 4 is diagnosed as healthy, 4-7 is intermediate, and 7-10 is considered high diversity, aka, BV. 

You may have noticed that “high diversity” isn’t a very specific diagnosis — and you’re right. Unfortunately, current diagnostic measures don’t tell you much about what other bacteria are present or any other relevant information about how they’re interacting in your vaginal microbiome. 

This is why we’ve created an at-home vaginal microbiome test, so you can understand all the bacteria present in your microbiome. Though it’s not a diagnostic test and shouldn’t replace the advice of your doctor, it can help you uncover what strains are present and in what capacity to understand how they may be contributing to any symptoms.

Fig 1 -> Bacteria that is adhered to vaginal epithelial cells, known as clue cells. The presence of these clue cells is one of the signs that the patient has bacterial vaginosis. CDC/ M. Rein

Can men get BV?‍

Only people with vaginas can develop BV because by definition it is an imbalance in the vaginal microbiome. However, male genitalia can harbor pathogens that disrupt the vaginal microbiome. 

How to treat BV 

BV is often treated with antibiotics prescribed by a doctor. Commonly used antibiotics include clindamycin and metronidazole, as well as alternatives such as tinidazole or secnidazole. Unfortunately, these are not great solutions for treating BV for good - while antibiotics clear up to 85% of bacterial vaginosis cases within a month, for over half of these patients, the infection will return within 6 months. Some studies show recurrence rates as high as 80%, 3 months after “effective treatment.” Doesn’t sound so effective to us! 

It’s important to note that each antibiotic works better on some strains of bacteria compared to others, and certain ones spare the protective bacteria while others do not (more on that here!). When battling recurrent infections, knowing what specific bacteria are in your microbiome may be useful data for selecting an antibiotic. 

We hope that further research into the vaginal microbiome can create an opportunity for more precise and effective treatments in the future. ‍In the meantime, our Evvy Experts can help provide insights based on your microbiome to share with your medical provider.

Why does my BV keep coming back?

One way to help prevent a BV recurrence is to take a probiotic with helpful strains of vaginal bacteria regularly. This ensures that protective bacteria are always being introduced to strengthen your natural defense against pathogens — even if you’re taking antibiotics.

Aside from medication, there are some everyday behaviors you can do to prevent BV from coming back: 

  • Avoid douching and feminine hygiene products, which can imbalance your microbiome 
  • Wipe front to back
  • Change your period products within the proper time frame
  • Stick to underwear that is loose-fitting, lightweight, breathable, and made from a natural fabric, and change it often
  • Wash sex toys with every use
  • Reconsider smoking and diet habits (smoking and unhealthy fats are linked to an increased risk of BV)