Endometrial receptivity, to test or not to test: the evidence on contemporary assays

Abstract

Despite improvements in in vitro fertilization success over the last 2 decades, the live birth rates do not exceed 65% even after transfer of a preimplantation genetic testing for aneuploidy normal blastocyst to a sonographically optimal endometrium. Consequently, there has been a search for more subtle endometrial factors that may deter sustained implantation and for treatments to mitigate these factors. Assays evaluating the window of implantation, markers of inflammation, normal vs. abnormal microbiome, and variations in the expression of endometrial proteins thought to be associated with implantation are commercially available and sought out by patients. The Endometrial Receptivity Assay aims to individualize embryo transfer timing but lacks sufficient data to support its use. Chronic endometritis may be associated with poor reproductive outcomes in some patients; however, accurate diagnosis is a challenge, and there is no high-quality evidence supporting routine assessment. Assessment of the uterine microbiome, ReceptivaDx, and the endometrial function test similarly do not have sufficient data to recommend routine testing in either the general infertility population or those who have experienced unsuccessful embryo transfer. Additional studies are needed to evaluate the endometrial contribution to implantation failure and what population, if any, may benefit from additional endometrial testing.