The Vaginal Microbiome – A Hidden Cosmos

In the last decades, the gut microbiome has entered the center of public interest. Various books and publications on the matter were like icebreakers. While we felt a bit at unease talking about our feces samples in public not too long ago, we are now openly discussing the bacterial colonization of our gut and effects on our wellbeing without any shyness. The gut microbiome might be most complex in our body, but it is not the only one, by far. Mouth and throat, skin, lung – all these body parts are specifically colonized by microbiota. Also, the cosmetics industry has committed to the microbiome issue. So, we have come quite a way in comparison to just a few years ago.

Taboo subject vagina

But although we may have overcome our shyness regarding gut and skin bacteria, there is still one topic that seems to be stigmatized: the vaginal microbiome. While we are casually talking about our inflammatory bowels, the unfulfilled desire to have children or a uterine infection are topics that we discuss we our gynecologist and our partner, at best, but strictly not in public. We are sparing you the next step of discussing what that says for our social double standard in times of the so-called sexual enlightenment. This article rather aims at finally spreading some facts on a body part that is at least influencing half of the population.

An ecosystem in constant change

A recently published survey by the Reproductive Biomedicine Journal summarizes the status of research on the vaginal microbiome to date. First, we have to notice that the microbiome is not the same for the entire life span of a woman. The microbiome of babies and infants resembles more or less the gut microbiome in its composition. In the course of the years and towards puberty, the vaginal colonization shifts towards Lactobacillus species. This acts as a precaution for a possible conception. Lactobacillus bacteria can metabolize sugar and other carbohydrates into lactic acids. These lactic acids let the pH value unfavorable for pathogenic bacteria and prevent infections.

It is well-known in today’s gynecology that miscarriage and premature birth are mostly caused by uterine infections. Often, bacteria enter the body over vagina and cervix and colonize the placenta. This changes the composition of the vaginal microbiome and pH value negatively for the embryo. Deformations, miscarriage or premature birth can be the result. So, an intact microbiome is an important prerequisite for a successful pregnancy.

A fragile system, subject to many influences

But it is not only that colonization by pathogenic bacteria that alters a vaginal microbiome. Also fluctuating hormone levels (in the course of a menstrual cycle, the course of a pregnancy, and during the lifespan of a woman) have an influence on the composition of the vaginal microbiome. During puberty, the level of estrogen and progesterone rises, fostering a colonization of Lactobacillus, which is the ideal basis for a pregnancy.

Furthermore, impacts like smoking, sexual activity, the intake of hormones (as contraceptives, for instance), increasing age, and also genetics, have an influence on composition and diversity of the microbiome. For example, the number of Escherichia coli bacteria and Candida fungi varies significantly between women using diaphragm vs. pill. In a nutshell, the vaginal microbiome is a highly complex system and its functionality depends on a number of factors and we often impact this system without even knowing.

Even ethnicity plays a role regarding the composition of the vaginal microbiome. Studies show that the pH value of Hispano and Black women’s vaginal microbiome is higher than the one of European and Asian woman. This suggests that also ethnicity plays a role for the vaginal microbiome.

Important conclusions for successful treatments

As often before in microbiome matters, the conclusion is to best disturb the complex microbial system as little as possible and let it limit the external factors to a minimum. Smoking, drugs, hormone therapies, and so on, are all factors that can destroy the fragile balance of that system. At the same time, as for any complex system, regulatory measures are extremely complicated. The use of antibiotics may be sensible in some situations, but before you vote for a therapy, be sure to evaluate the pros and cons thoroughly, because – naturally – antibiotics cut down the diversity of our microbiome and it has to recover from that impact (more about antibiotics).

In the course of a woman’s life, there might be situations, where the use of hormones, antibiotics and other medication may be justified. But if we decide to do so, the previously mentioned evaluation should be concluded, first. What phase of life is the woman in and what should her healthy microbiome ideally look like? Is a pregnancy planned? What treatments have been performed, so far? Considering all these questions, the result can look quite differently from case to case and from woman to woman. The more we know about the life cycle of a healthy vaginal microbiome, the more successful can future treatments be accomplished. As an example, a probiotics cure might be a smooth alternative to other medications: Link to study.

What about hygiene products?

There are medical treatments on the one side, but the daily question of what hygiene products women should or should not use, remains still unclear. The overall goal is to apply as little substances, no matter of what origin or for what reason. To clean your genital area, make sure to use pH neutral products without any additives. Most important, do not use mere “cosmetical” applications without any added value, such as perfumes. Ideally, the products should be tested “microbiome-friendly” to ensure the complex and fragile system stays balanced.

We are delighted to see that this body part is now also getting the attention that it deserves and hope that microbiome-friendly applications will be standard in the future.