Characterization of the Endometrial Microbiome in Patients with Recurrent Implantation Failure

Abstract

An abnormal endometrial microbiota has been associated with implantation failure; therefore, it may be important to evaluate it in order to improve reproductive outcomes in infertile patients. The main objective of our study was to compare the endometrial microbiome of patients with recurrent implantation failure (RIF) and control patients undergoing assisted reproduction treatment (ART). A prospective cohort study including forty-five patients with their own or donated gametes. The endometrial microbiome was analysed by massive sequencing of the bacterial 16S rRNA gene. Different bacterial communities were detected in RIF and control patients. Lactobacillus stands out as the most frequent genus, with 92.27% in RIF patients and 97.96% in control patients, and significant differences were reported between the two groups (p = 0.002). No significant differences were found regarding alpha diversity index. In beta diversity analysis, a significant trend was observed in the separation of the bacterial community between established groups (p < 0.07). Relative abundance analysis identified genera Prevotella (p < 0.001), Streptococcus (p < 0.001), Bifidobacterium (p = 0.002), Lactobacillus (p = 0.002) and Dialister (p = 0.003). Our results demonstrated the existence of an endometrial microbiota characteristic of RIF patients and showed that there might be a relationship between population of the endometrial microbiome and embryo implantation failure, providing us the possibility to improve clinical results in this patients.

Pilot Study on Next-Generation Sequencing Analysis of Vaginal Microbiota in Clinically Infertile Patients Treated with Probiotics

“…In a prospective cohort study by Koedooder et al, a cohort of 303 women were subject to pre-IVF vaginal sampling, revealing that individuals harboring an unfavorable vaginal microbiota composition exhibited a sevenfold lower likelihood of achieving pregnancy compared to those with a favorable profile [ 18 ]. Consistent findings indicated that infertile women, particularly those encountering recurrent implantation failure (RIF), exhibited decreased Lactobacillus growth and heightened Gardnerella growth, distinguishing them from their fertile controls [ 20 , 22 , 23 ]. Gardnerella species are linked to chronic inflammation and altered immune responses in the vaginal environment.…”

Friend leukemia integration 1 overexpression decreases endometrial receptivity and induces embryo implantation failure by promoting PART1 transcription in the endometrial epithelial cells

“…Endometrial infection and inflammation can lead to aberrant local immune responses in the endometrium and consequently prevent embryo implantation ( Wang et al, 2022 ). Furthermore, the dysregulation of endometrial microbiota has been associated with implantation failure ( Lozano et al, 2023 ). Endometrial receptivity refers to the ability of the endometrium to allow the localization, adhesion, penetration, and implantation of blastocysts, as well as to enable embryo implantation and development ( Lessey & Young, 2019 ).…”

The Impact of the Microbiological Vaginal Swab on the Reproductive Outcome in Infertile Women

“…Consequently, this study showed the superiority of the vaginal swab over the endometrial sample as a biomarker for repeated implantation failure. The prospective cohort study by Lozano et al also compared the endometrial microbiome of a group of patients diagnosed with RIF with that of a control group without RIF [ 15 ]. Here, in contrast to the study by Ichiyama et al, a significantly lower rate of lactobacilli was found in the patients with RIF.…”