Objective: Structure and correct function of endometrium is necessary for embryo implantation, pregnancy development and childbirth. It is a result of many factors - anatomical and histological structure, hormonal effects and signalling pathways at the molecular genetic level. A little known phenomenon is the presence of microorganisms on the endometrium. Traditionally, the uterine cavity was considered sterile, but new findings have been changing this view fundamentally. The aim of this work is to present new findings on endometrial microbiome and its importance for embryo implantation and development.

Design: Review article.

Setting: Department of Obstetrics and Gynecology, Faculty of Medicine, Masaryk University and University Hospital Brno; Department of Obstetrics and Gynecology, University Hospital Faculty of Medicine, Palacky University Olomouc.

Methods: PubMed was searched for articles in English indexed until 30th June 2018 with terms of „uterine microbiome analysis“ and „endometrial receptivity“.

Results: The vital information on bacterial colonization of endometrium brought new diagnostic methods for their detection based on ribosomal RNA analysis in 16S subunit, which are capable of detection and exact identification of bacteria that cannot be detected by classical cultivation methods. The endometrial microbiome is assumed to modulate the function of endometrial cells and local immunity system, it prevents growth of pathogenic microorganisms by its presence and production of protective substances.

Conclusion: Endometrial microbiome seems to be important factor of endometrial receptivity.