The Vaginal Microbiome: What You Need to Know

Within each of us is a microscopic world made up of billions of tiny organisms like bacteria, fungi, viruses, and more. These organisms are not a part of our bodies, like our cells or organs, but instead are separate living things that reside inside of us. Together, these microorganisms make up communities within us known as microbiomes. 

You may be familiar with the term microbiome as it refers to gut health, but microbiome communities exist in other places too. In this article, we’ve gathered insights specific to the vaginal microbiome. 

Read on to learn all about the vaginal microbiome and its impacts, and to learn how to have your best vaginal health yet. 

How the Vaginal Microbiome Works

The vaginal microbiome is a part of the overall human microbiome.^[1] Within every person’s vagina is a multifaceted community of billions of microorganisms like yeast and bacteria. The vaginal microbiome is an ever-changing thing; it’s in constant flux throughout the course of one’s life.^[2]

The microorganisms in the vaginal microbiome all have a relationship with the host organism (in this case, you are the host organism!). Some of these microorganisms are beneficial to your vaginal health, like “good” bacteria.^[3] 

On the other hand, some of these are “bad”, or pathogenic, meaning they can cause damage or harm to the host organism.^[4] 

Good or bad, each and every one of these organisms makes up the vaginal microbiome.

The 5 Vaginal Community States (CST)

When it comes to the vaginal microbiome, the term “balance” is often used to describe optimal vaginal health. 

A “balanced” vaginal microbiome is when “good” bacteria dominate, which can help fight off or keep potentially harmful microorganisms to a minimum. 

While each vaginal microbiome is unique, the balance of each vaginal microbiome tends to fall into 5 different categories, known as the vaginal community states. These were distinguished in a study examining 369 healthy, reproductive-aged women in the United States, based on composition and the presence of vaginal bacterial species.^[5] 

These community states are characterized by the most abundant type of bacteria within the vaginal microbiome. They are as follows:^[6] 

• CST-I: Dominated by Lactobacillus crispatus 
• CST-II: Dominated by Lactobacillus gasseri 
• CST-III: Dominated by Lactobacillus iners 
• CST-IV: Lacks a dominant bacteria, instead contains diverse bacteria with low presence of protective lactobacilli
• CST-V: Dominated by Lactobacillus jensenii

It’s important to note that more research is needed; it continues to be an ongoing process to understand how these community types evolve and change over time.

How It Works

Community states I, II, III, and V are considered to be symbiotic, or healthy, states. The vagina provides a nutritious and comfortable environment for microorganisms to exist, while in turn lactobacilli, the “good” bacteria, produce antimicrobial and anti-inflammatory factors that create an environment that is inhospitable to foreign, potentially harmful microorganisms.^[2] This results in a generally healthy and well-protected vaginal microbiome and overall good vaginal health.

Beyond these beneficial bacteria, other components play a crucial role in maintaining this delicate balance. One such important player is lactoferrin, a naturally occurring protein found in the vagina, as well as in other bodily fluids including saliva, tears, and breast milk^[7]. Lactoferrin serves as a prebiotic and supports lactobacilli bacteria in the vagina. It has been shown to help lactobacilli create biofilm and adhere to vaginal cells, further enhancing the defense mechanisms of the vaginal microbiome.^[8] 

The Vaginal Microbiome and Infections

When a vaginal microbiome is unbalanced, like those in community state IV, it is known to be in a state of “dysbiosis”. Vaginal microbiomes in this state have a greater risk of infection.^[15] 

Remember that the vaginal microbiome is always fluctuating and changing, so dysbiosis can be an extremely temporary state, leaving little risk for infection—or it can be a lasting condition and open the doors to a host of infections.^[15]  

Vaginal Infections and their Causes

Many vaginal infections are extremely common and easily treatable. These include:

• Bacterial vaginosis: BV is the most common vaginal condition in females ages 15-44 and is the most common cause of abnormal vaginal discharge. BV occurs when there is a decrease in lactobacilli, allowing “bad” bacteria to thrive and dominate.^[15]
• Yeast infections: Most commonly caused by Candida albicans and occurs when the population of lactobacilli declines, allowing yeast to dominate.^[15]
• Cytolytic vaginosis: Rather than resulting from a lack of lactobacilli, CV occurs when there is an overgrowth of lactobacilli in the vaginal microbiome, which can rupture protective vaginal epithelial cells. The epithelium is a layer of tissue that lines the surfaces and cavities of organs throughout the body and acts as a protective barrier, epithelial cells make up this epithelial tissue. Cytolytic vaginosis can lead to abnormal discharge, itching, and pain.^[15] 

The Impact of the Vaginal Microbiome on Overall Health

The vaginal microbiome plays a significant role in the overall human microbiome. As a result, the vaginal microbiome can have dramatic impacts on not only vaginal health, but on many different facets of your health. Remember that bacteria impacts each of our bodies differently and to a different level of severity. We also want to remind you that we have gathered this information as a resource to support your research – but it is crucial to visit your doctor with any health concern as soon as possible. 

Reproductive Impacts

Studies have shown that the vaginal microbiome plays a significant role in terms of reproduction. Poor health of the vaginal microbiome can dramatically increase the risk of reproductive issues, including:^[15]

• Infertility: One study showed that certain non-lactobacilli bacteria like Ureaplasma and Gardnerella in the vagina and cervix were more abundant in those struggling with fertility. Whereas the prominence of Lactobacillus crispatus specifically may result in more successful IUI (intrauterine insemination) procedures.
• Pregnancy outcomes: Several studies have shown normal pregnancy outcomes in women who have sustained a lactobacilli dominated vaginal microbiome for their entire pregnancy. 
• Miscarriages: A study showed that some of those who experienced first-trimester miscarriages were associated with lactobacilli depletion and disproportionately had a vaginal microbiome in community state IV (a lack of lactobacilli dominance).

Gynecologic Cancer

Research has also suggested a potential link between the vaginal microbiome and certain types of gynecologic cancers. ^[15]

• Cervical cancer: Studies have reported an association with non-lactobacilli-dominated vaginal microbiomes and HPV (human papillomavirus). In addition a significant increase in vaginal pH, which is tied to a lack of protective lactobacilli bacteria was related to not only the severity but also the progression of cervical disease.
• Ovarian cancer: A few studies show an association between vaginal dysbiosis and the development of ovarian carcinoma, however the link remains unclear. Proving causation in cancer is challenging due to the interactions between potential contributing factors. The female reproductive tract may be more vulnerable to microbial disruptions because it is exposed to the external environment and contains a diverse microbiota, similar to the gut. Certain microbes can trigger inflammatory responses, while others have anti-inflammatory effects, and a shift in this microbial balance may lead to an impaired immune response. However, more research is needed to fully understand this association.

Urinary Health

The vaginal microbiome has also been shown to influence urinary health. Dysbiosis of the vaginal microbiome is linked to acute and recurrent urinary tract infections. This may also be why menopause increases the risk of UTI, as the presence of lactobacilli drops dramatically after menopause due to a decline in estrogen, allowing other bacteria to flourish.^[15]

Ways to Support a Healthy Vaginal Microbiome 

Fluctuations in your vaginal microbiome are normal, as are occasional imbalances. However, there are steps you can take to be proactive with your vaginal microbiome and create an environment for a healthy and balanced vaginal microbiome.^[15]

• Stay dry whenever possible: Dry your vaginal area after a shower and avoid sitting in wet clothes whenever possible, like after swimming or the gym. 
• Wear cotton underwear: Cotton underwear allows your vagina to breathe and minimizes excess moisture from sweat.
• Wash your vaginal area with water: Scented soap isn’t necessary to clean your vagina.
• Never douche: This is an unnecessary practice that can eliminate the good bacteria in your vaginal microbiome, opening the doors for bad bacteria and fungi to take over.
• Use barriers during sex: Condoms and other sexual barriers can protect your vagina from foreign organisms.
• Take probiotics: Probiotic supplements can support your whole-body microbiome.

Your vaginal microbiome plays a significant role in both your vaginal and overall health. By fostering a healthy vaginal microbiome, you may lower your risk of infection or serious illness.