Endometrial microbiota in infertile women receiving in vitro fertilization (IVF)-embryo transfer. Endometrial microbiota in infertile women receiving in vitro fertilization (IVF)-embryo transfer

It has recently been shown that microbiota of the endometrial cavity of patients receiving treatment of in vitro fertilization and embryo transfer (IVF-ET) was correlated with the treatment outcome. However, investigators of that study analyzed microbiota from only endometrial fluid samples.Previously, using paired samples from the same women, we have identified quantitative and qualitative differences between endometrial fluid and tissue samples obtained from the same woman. Specifically, the numbers of taxa identified per 1000 sequencing reads, bacterial diversity, and evenness in fluid samples were smaller than those in tissue samples (Clin Chem. 2018;64:1743-52). Thus, sampling from both endometrial fluid and biopsy allows a more comprehensive view of microbial colonization. To address this, we profiled the endometrial tissue microbiota of IVF-ET patients and investigated whether any characteristics were correlated with the treatment outcome.