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Is it possible that your microbiota affects your chances of conceiving? More and more studies reveal that billions of microorganisms that live in a woman’s body—especially in the intestines, vagina and endometrium—can affect her reproductive health. But how exactly does your microbiota impact fertility? And could a slight alteration in this delicate bacterial ecosystem hinder natural pregnancy or assisted reproduction techniques?
In this article we will explain the correlation between microbiota and fertility, analyse how intestinal and vaginal dysbiosis can affect conception and what strategies can help stabilise your microbiome in order to improve your chances of getting pregnant.
What is microbiota and why is it so important?
Before explaining the correlation between microbiota and fertility, we need to establish that microbiota is the range of microorganisms (mainly bacteria and fungi) that naturally inhabit various areas of our bodies, such as our gut, mouth, skin, vagina and uterus. Traditionally, microbiota used to be mostly associated with digestion. Now we know about a range of its other functions, including:
- regulation of the immune system;
- involvement in the production and metabolism of hormones;
- protection from infections;
- influence on the absorption of essential nutrients.
Close link between microbiota and fertility
In recent years, scientists have discovered that the influence of microbiota on fertility is greater than we had thought. We are starting to realise how microbiota in our reproductive system may affect the quality of gametes, endometrial receptivity or even implantation.
Precisely, some studies point out that the imbalance in the bacteria composition, known as intestinal or vaginal dysbiosis, may be related to unexplained infertility, implantation failures or recurrent miscarriages.
How does microbiota affect conception?
In the context of fertility, scientists are looking into three types of microbiota that are the most relevant for conception:
1-Vaginal microbiota
The first natural barrier that protects female reproductive organs against pathogenic microorganisms. This microbiota is mostly composed of Lactobacillus species (L. crispatus, L. jensenii, L. gasseri) and their primary function is to maintain the pH balance, which prevents certain infections that, if spread to uterine tubes or endometrium, could affect fertility. In short, vaginal microbiota plays a crucial role in creating a favourable environment for conception.
2-Endometrial microbiota
Even though for many years the endometrium was thought to be a sterile organ, now we know that this inner layer of a healthy uterus, the place where implantation occurs, does indeed contain nonpathogenic bacteria, viruses and other microorganisms, collectively referred to as endometrial microbiota.
Recent studies suggest that having a balanced endometrial microbiome is crucial for a proper implantation of an embryo [1]. Conversely, if endometrial dysbiosis occurs, some pathogenic bacteria can proliferate, which may result in infertility. This holds true for bacteria that cause sexually transmitted diseases, such as gonorrhoea or Chlamydia trachomatis, as well as some species like Mycobacterium tuberculosis, which causes genital tuberculosis.
Various studies have shown that women whose uterine cavity has a vaginal flora abundant in Lactobacillus bacteria display higher chances of successful implantation, gestation and live birth, in comparison to women with low number of Lactobacillus. Therefore, if the majority of the bacteria in the endometrium is not of the genus Lactobacillus, the effectiveness of an assisted reproduction treatment can decrease significantly.
3-Intestinal microbiota
The intestinal microbiota is a community of living microorganisms (primarily bacteria, but also viruses, fungi and others) that inhabit your gastrointestinal tract, mainly the large intestine. This complex ecosystem, which can weigh up to 2 kilograms in adults, contains more than 100 trillion microorganisms belonging to hundreds of different species. This intricate microbial world upholds a symbiotic relationship with our organism. Its stability is crucial not only for our digestive health, metabolism and immune system, but also for our reproductive capacity.
Effects of intestinal dysbiosis on reproductive health
An intestinal dysbiosis (or imbalance) can also affect ovulation, oocyte quality and endometrial receptivity.
It may be caused, for instance, by the bacterium Helicobacter pylori residing in the stomach, associated with digestive problems, such as gastritis or ulcers. Recent studies suggest that infections triggered by this bacterium can affect hormonal balance and interfere with the general health of the reproductive system, which might lead to infertility. To be precise, a decrease in the quality of sperm of men infected by H. pylori strains has been observed. Infected women have displayed specific antibodies in their cervical mucus that reduce the motility of sperm. The antibodies have also been present in follicular fluid, where they could cross-react with spermatozoa [2].
Moreover, an intestinal dysbiosis can contribute to the development of dysbiosis in the reproductive system. Therefore, it is important to maintain a healthy intestinal microbiota in order to improve the reproductive health.
However, the correlation between microbiota and fertility is not only relevant for women. The latest studies imply that the intestinal dysbiosis can affect the quality of male sperm due to an increase in the level of oxidative stress [3].
Ways to improve microbiota and fertility
Before you begin assisted reproduction treatments, we advise you to take care of your microbiota using some of the following strategies:
- Follow a diet rich in fibre, antioxidants and healthy fats. You can also include foods abundant in probiotics, such as yoghurt, kefir or fermented cabbage, and foods containing prebiotics, such as fibre crops that our bacteria feed on and that help to maintain a healthy balance.
- Take probiotic supplements (oral or vaginal) that can repopulate your flora with healthy bacteria, specifically bacteria of the genus Lactobacillus.
- Avoid unnecessary use of antibiotics. Antibiotics alter the intestinal and vaginal microbiota. Take them only if it is truly necessary and always under medical supervision.
- Manage stress. It has been proven that chronic stress can negatively impact the microbiota due to the gut-brain axis. Chronic cortisol elevation alters your intestinal microbiota. That is why it is advisable to relieve stress with yoga, meditation or therapy.
When is it necessary to analyse your microbiota?
Even though we already have reasons to believe in the clear correlation between microbiota and fertility, further research is needed in this regard in order to reach definitive evidence. That explains why microbiome analysis is not a part of routine screenings that we perform at the beginning of assisted reproduction treatments.
However, in the case of recurrent miscarriages or implantation failures, a microbiome analysis can help us improve the results of certain assisted reproduction treatments and clear up doubts regarding sterility or infertility problems of unknown origin.
At Tambre we design fully personalised treatments, and should any hindrances occur (like miscarriage or implantation failures), we might implement a microbiome analysis. If we detect dysbiosis, we can prescribe a probiotic treatment that will improve the balance in microbiota before we begin a new assisted reproduction treatment.
At Tambre we know that there is still much to study. We work tirelessly to implement the latest scientific breakthroughs into our personalised fertility treatments. Research on microbiota can be a useful tool to improve results for certain patients.
Do you still have questions regarding the impact of microbiota on fertility? Contact us at 91 411 61 11 to make your first appointment. At Clínica Tambre we listen to you, we answer your questions and we accompany you, backed by the most advanced science and cutting-edge technology.