How does adenomyosis impact endometrial receptivity? An updated systematic review of clinical and molecular insights

Objective:To summarize current knowledge regarding the outcomes of assisted reproductive technology (ART) in patients with adeno-myosis, offer insights into the defects in the regulation of endometrial receptivity, and discuss the implications for the clinical manage-ment of adenomyosis and infertility. Evidence Review:We conducted a comprehensive literature search of PubMed for original and review articles published in English upto June 2022 in the following areas: adenomyosis and infertility; ART; endometrial receptivity; and embryo implantation. Results:Adenomyosis may have a negative impact on endometrial receptivity, reducing the probability of conception by ART. Theseverity of adenomyosis seems to be associated with the severity of the impairment in receptivity, and before treatment with agonadotropin-releasing hormone agonist before frozen-thawed embryo transfer may restore endometrial receptivity. Molecularanalyses demonstrated that genes associated with endometrial receptivity are aberrantly expressed in the eutopic endometria ofwomen with infertility with adenomyosis. Hyperproliferation of the endometrial epithelium, impaired decidualization, progesteroneresistance, altered expression of adhesion molecules, a hyperinflammatory microenvironment, chronic endometritis, and abnormaluterine contractility seem to be involved in the impairment of endometrial receptivity. Conclusion:Uterine adenomyosis reduces endometrial receptivity via several mechanisms. In addition, data suggest that the etiologicmechanism of adenomyosis is responsible for impaired endometrial receptivity. Before treatment with a gonadotropin-releasinghormone agonist before frozen-thawed embryo transfer may ameliorate the defects in the uterine environment, probably byrestoring the expression of genes that are essential for embryo implantation. Further research using animal models should aim toadditionally clarify the relationship between adenomyosis and infertility to refine the treatment strategies for women with infertilitywith adenomyosis. (Fertil Steril Rev & Ograve;2023;4:15-25.& Oacute;2023 by American Society for Reproductive Medicine.)