This article explores a specific part of the human microbiome that has not gained as much attention as the well-established gut or skin microbiome – yet. It delves into the exciting microcosm of the vaginal microbiome and breaking taboos by discussing its role in women’s health, its implications for pregnancy, birth and beyond, as well as the future of product formulation and health-conscious marketing in the cosmetic industry.
Thanks to the growing awareness and scientific research about the gut microbiome, nowadays, words like gut flora, stool sample and probiotics are well-known and more commonly used than even a few years ago. This field of research opened the door for further studies about different kinds of microbiomes in the human body, like the oral and skin microbiome.
Another microbiome, that is rarely publicly talked about, is the vaginal microbiome. Even though most women worldwide have experienced different kinds of uncomfortable symptoms that disturb their daily life, topics like yeast infections, infertility, intimate personal care and reproductive health are still taboo and mostly only talked about behind closed doors or at obstetrics/gynecology offices.
This makes it harder for women to open up and oftentimes leaves them feeling alone with their problems. Facing the decision of either resorting to another course of antibiotics – that often do not help or cause other problems – or using commercial intimate care products that claim to help with vaginal dryness or ‘unwanted smells’.
Luckily, this is changing now and knowledge about the vaginal microbiome is spreading. Like with everything, knowledge is power and learning more about the vaginal microbiome will empower women to take care of their intimate wellbeing.
In order to raise awareness about all things microbiome, MyMicrobiome created the educational platform MyMicrobiome.info as well as the world’s first and only certification mark for ‘Microbiome-friendly’ personal care products and textiles, working with the cosmetic industry to change the standards of beauty and health.
To fully understand where we are right now in regards to vaginal health, we first have to take a look at the history of women’s health in general. Where we discover that it is still a fairly new area of scientific research.
The science and history of women’s health
In the past, there were thought to be no differences in the physiology of male and female bodies – except for the reproductive organs. But not all sex-related differences are due to hormones.  Until 1993, women of reproductive age were excluded from drug trials due to the potential risk for their offspring. This means, clinical studies with women have only been done for less than 30 years, which led to a shortage of data about the effects of drugs on female bodies. 
Most research studies before the early 2000s were done with only male subjects and those including females did not analyze their data in regards to sex. Also, medical physiology textbooks and curriculums did not address further physiological differences between the sexes until after 2006.  And even now, there is still a gap in the knowledge about male and female health, as a 2019 study from Copenhagen showed. It found that across 770 diseases, women are diagnosed about four years later than men. 
As for the vaginal microbiome: It has been studied for two decades and its importance has been recognized . Yet, the research was mainly focused on its role in childbirth.
What is the human microbiome?
The term ‘microbiome’ refers to the trillions of microorganisms like bacteria, fungi and viruses that live in and on the human body. Different parts of the body are host to subsets of microbiomes like the nasal, oral, skin or gut microbiome. Each is its own ecosystem. Inhabited by different communities of microorganisms, called microbiota.
Even though this field of study is fairly new, too, the last 20 years have undoubtedly shown the microbiome’s crucial role in every aspect of health, from digestion and metabolism to immune system, brain and heart function, and many others. A microbiome that is out of balance, or dysbiotic, can lead to disorders like inflammatory bowel disease, diabetes, obesity, allergies, and cancer. 
And what about the vaginal microbiome?
The microbiome in the vagina is a dynamic ecosystem that changes during a woman’s entire life and is as unique as her fingerprint. It is characterized by a low number of microbial species and is mainly dominated by different types of Lactobacillus. Compared to the gut, that houses thousands of bacterial species, the vaginal microbiome only hosts about 200 species. 
Whereas microbial diversity is a marker for health in other microbiomes (like gut and skin), it is actually a potential factor for dysbiosis in the vaginal microbiome. 
Its composition depends on factors like genes, age, ethnic background, environment and hormone levels. It is also influenced by the menstrual cycle, sexual partners and lifestyle factors. Interestingly, differences in the microbiota can especially be seen between different ethnic groups.
In childhood, the vaginal microbiome is mainly made up by anaerobic microbiota and a mix of skin and gut microbes. With the rise of estrogen levels during puberty and the preparation for potential pregnancy, glycogen is accumulated in the vaginal epithelium. This aids the growth of microorganisms like Lactobacilli, that metabolize glycogen to glucose and lactic acid. With lower estrogen levels in (post-)menopausal women, glycogen is less available, decreasing the number of Lactobacilli. This can result in less protection from pathogenic organisms. 
Different types of vaginal microbiomes
Lactobacilli are the cornerstone species for the vaginal milieu of women of childbearing age. The most dominant species are the facultative anaerobic Lactobacillus crispatus, L. gasseri, L. iners and L. jensenii. Other, anaerobic species are Prevotella, Dialister, Atopobium, Gardnerella, Peptoniphilus and Megasphaera.
Lactobacilli protect the vaginal flora from harmful microorganisms, that could trigger bacterial, fungal and viral infections. They produce antibacterial compounds like bacteriocins as well as the powerful antiseptic agent hydrogen peroxide (H2O2), lactic acid, a potent bactericide and virucide, bacterozines. The formation of biofilms, the competition for nutrients or the modulation of the immune system are used to inhibit pathogenic microbes. 
Lactic acid is responsible for the low, i.e. acidic, vaginal pH, which is usually defined as normal between 3.8 - 4.4 . In comparison: The average pH of saliva is 6.7 and the different parts of the gut are between 5.7 and 7.4 [12, 13].
The vaginal pH varies between women of different ethnic backgrounds: Hispanic and black women have a higher vaginal pH of 5.0 and 4.7, compared to Asian (4.4) and white women (4.2). This can be explained with different genes, differences in the innate and adaptive immune systems, sexual behaviors, hygiene, etc. 
While every woman has her own unique vaginal microbiome, research found five major types of microbial communities. These so-called ‘Community-State Types’ consist of different amounts and species of Lactobacillus. Four of the types are dominated by Lactobacilli. The fifth more by anaerobic species (Figure 1).
Ethnic differences are also seen here: The vaginal microbiome of Asian and white women is mainly dominated by Lactobacilli, which is not necessarily the case for black and Hispanic women, who seem to have a more anaerobic flora (Figure 2). This also leads to the above-mentioned differences in pH levels. 
To see the figures, click here.
Factors that disrupt microbial balance
The vaginal microbiome is healthy, when it is in balance or homeostasis. But everything that comes in contact with this fragile ecosystem, can potentially cause disruption, leading to dysbiosis and unwanted symptoms.
This includes things like tampons, menstrual pads, lubricants, intimate showers, lotions, parfums, underwear (shape and fabric), sexual partners, condoms, sex toys, as well as less obvious factors like antibiotics, medicines, hormonal contraceptives, smoking, stress, etc.
The results of a dysbiotic vaginal microbiome
With the Lactobacilli’s antimicrobial defenses, the vaginal microbiome in its natural state can fend off pathogenic invaders. If, however, the microbial equilibrium is disrupted by the above-mentioned factors, the number of beneficial microbes decreases and pathogenic organisms like Gardnerella vaginalis and Atopobium vaginae can grow. 
This can result in the most common dysbiotic state in women of reproductive age: Bacterial vaginosis. This condition is characterized by itching, unusual discharge, fishy odor, and burning and can lead to reproductive health problems like pelvic inflammatory disease, sexually transmitted infections, preterm birth, low birthweight, miscarriage and maternal and neonatal infections. Other common diseases related to microbial dysbiosis are vaginal candidiasis or yeast infections and urinary tract infections. 
The dangers of the most common treatment
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To see the rest of the references, see article here.