Vaginal Microbiome

Vaginal Microbiome Overview

The vagina is a fascinating organ that connects the internal reproductive organs to the outside world. Any disruption to the vaginal microbiome could potentially lead to problems within the vaginal canal and beyond.

The vaginal microbiome has a role in many physiological and pathological processes, ranging from vaginal infections to fertility issues. The microbiome is a complex ecosystem of bacteria and fungi that live within the vagina. In the absence of pathological processes, the microbiome has a symbiotic relationship with the vagina.

The microorganisms that reside inside the vagina prevent the overgrowth of opportunistic pathogens that cause bacterial vaginosis (BV) and yeast infections. They also play a role in pregnancies and cancer prevention.

With all of that said, we need to remember that the field of studying the human microbiome is relatively new, with a lot of exciting research. Albeit, most of the research is focused on the gut microbiome.

In this article, we will explain everything there is to know about the vaginal microbiome.

The Vaginal Microbiome Explained

The vagina is home to various microbes, but lactobacilli plays a particularly important role in maintaining the health of the vaginal microbiome.

These bacteria help to prevent the growth of pathogens in the following mechanisms:

  • Synthesizing lactic acid to keep the vaginal pH low (3.8-4.5)
  • Occupying space on the vaginal wall and inhibiting the growth of other pathogens
  • Producing bacteriocins (a natural antimicrobial agent) to inhibit the multiplication of opportunistic bacteria
  • Dampening inflammation

Measuring the acidity of the vagina (via a vaginal pH test) can tell us a lot about lactobacilli’s presence in the vaginal microbiome.

If the vaginal microbiome lacks lactobacilli, it can become more susceptible to colonization by pathogens, a condition known as vaginal dysbiosis.

In case of dysbiosis, the vagina may have a high diversity of bacteria, including opportunistic microbes such as E. coli, Gardnerella, and Mycoplasma. These bacteria lead to a burning sensation, itching, irritation, and pain. They can also cause infections, such as bacterial vaginosis (BV) and urinary tract infections (UTIs).

Relationship between your Vaginal Flora and Infections

While the vaginal microbiome hosts protective microbes, it can also harbor bacteria and fungi that cause infections. Disruptions to the vaginal microbiome can create an environment for these harmful microbes to thrive, leading to infections.

Bacterial vaginosis (BV) is the most common vaginal infection. Approximately 1 in 3 women will develop BV each year. However, up to 84% of these cases are asymptomatic. BV affects Black and Hispanic women more than white females. The exact reasons are still poorly understood.

Dysbiosis of the vaginal microbiome can also lead to other types of infections, such as:

  • Yeast infections
  • Aerobic vaginitis (AV)
  • Cytolytic vaginosis (CV)

These infections have similar symptoms to BV, including itchiness, abnormal discharge, and burning. As a result, it can be very difficult to tell them apart.

It is not uncommon for people to experience recurrent infections. Aside from BV, 1 in 3 women will develop a urinary tract infection (UTI) by the age of 24, and half of all women will experience a UTI at some point in their lifetime. Similarly, about 75% of women will experience a yeast infection at least once in their lifetime.

Testing the vaginal microbiome can improve care for those suffering from recurrent infections and other vague health problems. It can also improve our understanding of the vaginal microbiome and how to address its issues.

Vaginal Microbiome Impact On Your Health

Another reason to focus on the vaginal microbiome is the recent research, which suggests that this collection of microorganisms plays a vital role in female health.

For instance, the classic bacteria of the vaginal microbiome, lactobacilli, seem to protect the body against all sorts of pathological states, including immune dysfunction, low-grade inflammation, and the growth of opportunistic microorganisms.

Additionally, the type and number of bacteria in your vaginal flora will determine the risk of:

  • Pelvic inflammatory disease
  • Pregnancy complications (e.g., miscarriage, preeclampsia, preterm birth, neonatal problems)
  • Failed IVF cycles and other fertility issues
  • Cervicitis
  • Ovarian, cervical, and endometrial cancers
  • Toxic shock syndrome (TSS)

Evaluating the composition of your microbiome can help you assess your risk of certain maladies and take the necessary precautions to mitigate them.

Categorization of Microbiomes

Similar to blood types, scientists managed to categorize different types of microbiomes based on their composition. We refer to these categories as Community State Types (CSTs).

While your type of CST will give us a lot of information about the protection you get from certain diseases, you can still shift between different CSTs.

Most people have one of these CSTs based on the dominant species of lactobacilli:

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

If you are wondering about type 4, it is for people without a dominant species of lactobacilli. Those who experience recurrent bacterial infections may belong to this category due to vaginal dysbiosis. However, that is not the full story. You see, some people with type 4 microbiome may be otherwise very healthy. This is why scientists have divided this microbiome into 5 subcategories.

Changes To Your Microbiome

During your lifetime, the vaginal microbiome undergoes several changes. There are a number of factors that could potentially modify the composition of your microbiome, including:

  • Sexual intercourse with multiple partners
  • Changing your birth control method
  • Pregnancy
  • Menopause

Your everyday activities can also play a role in the composition of your vaginal microbiome, including:

  • Taking certain pharmacological drugs (e.g., antibiotics) and supplements
  • Smoking
  • Stress
  • Applying vaginal products
  • Hormonal fluctuations