How the Endometrial Microbiota Influences Fertility

The endometrium must host a balanced microbial ecosystem. The endometrial microbiota, composed of a community of bacteria and other microorganisms, plays a crucial role in endometrial receptivity and the success of fertility treatments.

Endometrial Microbiota and Its Relationship with Fertility

Recent studies have shown that a predominance of beneficial bacteria, such as lactobacilli, is associated with higher implantation rates and fewer pregnancy complications. Conversely, an imbalance in this microbiota, known as dysbiosis, can create a hostile environment for the embryo, increasing the risk of implantation failure, miscarriage, and preterm birth.

Understanding the Importance of Endometrial Microbiota

Lactobacilli produce lactic acid, which maintains an acidic pH in the endometrium, inhibiting the growth of pathogenic microorganisms. Additionally, they modulate the local immune response, promoting a tolerant environment for the embryo.

An imbalance in the microbiota, on the other hand, can trigger chronic inflammation, disrupting endometrial receptivity and hindering implantation. Dysbiosis has also been linked to the production of toxic substances that may harm the embryo or interfere with its development.

Dysbiosis has been associated with conditions such as:

• Embryo implantation failure: An altered endometrial environment can prevent proper embryo adhesion and development.
• Recurrent miscarriage: The presence of pathogenic bacteria, such as Gardnerella vaginalis or Escherichia coli, can cause chronic inflammation that compromises pregnancy viability.
• Preterm birth: An altered uterine microbiome can trigger an inflammatory response, increasing the risk of complications during pregnancy.

Assessing and Modulating the Endometrial Microbiota

Evaluating the endometrial microbiota is crucial to understanding its impact on fertility and developing effective modulation strategies. Traditionally, DNA sequencing techniques are used to identify and quantify the different bacterial species present in the endometrium, revealing possible dysbiosis.

The connection between alterations in reproductive microorganisms and infertility has been extensively studied by Dr Laura Medina, a researcher at Integrated Genetic Laboratory Services (IGLS) in Alicante. After years of research, Medina has identified specific microorganisms involved in endometrial dysbiosis, a condition linked to difficulties in conceiving.

As a result of her work, Medina and her team developed MicroBioMap®, an innovative test designed to assess the health of the endometrial microbiota. Below is a video where Laura explains the importance of microbiota in infertility issues discovered through her research.

MicroBioMap®: A Precise Analysis of the Endometrial Microbiota

MicroBioMap® is an advanced molecular test that provides a detailed analysis of the microbial composition of the endometrium, specifically designed to evaluate its influence on female fertility. Using high-resolution quantitative PCR, MicroBioMap® detects the presence of 18 pathogenic microorganisms (including fungi, bacteria, and protozoa) associated with chronic endometritis, as well as four species of Lactobacillus, known for their beneficial effects on reproductive health.

Advantages of MicroBioMap®

• Accurate detection: Identifies a selected set of microorganisms relevant to fertility.
• Detailed quantification: Determines the level of each detected species, normalised per human cell, and its relative abundance within the total microbial community.
• Valuable insights: Provides information on the uterine environment and its suitability for embryo implantation, including the detection of pathogens linked to chronic endometritis.
• Personalised treatment: Allows doctors to choose targeted treatments to eliminate pathogens and restore microbiota balance.
• Improved reproductive outcomes: Enhances the chances of success in assisted reproductive techniques, particularly in women with recurrent implantation failure, miscarriages, or suspected chronic endometritis.

MicroBioMap® Process

The test is performed using an endometrial biopsy, from which microbial DNA is extracted. Through quantitative PCR, the presence and quantity of selected microorganisms are analysed.

Modulating the Endometrial Microbiota

Once the microbiota has been assessed, modulation strategies can be implemented to restore balance. These may include:

• Probiotic administration, introducing beneficial bacterial strains.
• Prebiotics, which promote the growth of beneficial bacteria.
• Selective antibiotics, to eliminate pathogenic microorganisms.

The choice of intervention depends on the test results and the individual needs of each patient. If you are unsure whether this test is right for you, do not hesitate to consult our specialists.