FERTILITY, IVF AND REPRODUCTIVE GENETICS: Edited by Emre Seli and Juan Antonio García VelascoUnderstanding and improving endometrial receptivityMiravet-Valenciano, Jose A.a,*; Rincon-Bertolin, Alejandroa,*; Vilella, Felipeb,†; Simon, Carlosb,c,†Author Information aIgenomix, Parc Cientific Valencia University, Paterna bFundación Instituto Valenciano de Infertilidad (FIVI), Department of Obstetrics and Gynecology, Valencia University, Instituto Universitario IVI/INCLIVA, Valencia, Spain cDepartment of Obstetrics and Gynecology, School of Medicine, Stanford University, California, USA *Dr Jose A. Miravet-Valenciano and Dr Alejandro Rincon-Bertolin are considered co-first authors and contributed equally to this work. †Dr Felipe Vilella and Dr Carlos Simon are considered co-last authors and contributed equally to this work. Correspondence to Felipe Vilella, Fundación Instituto Valenciano de Infertilidad (FIVI), C/Catedratico Agustin Escardino 9, 46980 Paterna (Valencia), Spain. Tel: 0034963903305; e-mail: email@example.com Current Opinion in Obstetrics and Gynecology: June 2015 - Volume 27 - Issue 3 - p 187-192 doi: 10.1097/GCO.0000000000000173 Buy Metrics Abstract Purpose of the review For a successful pregnancy, the synchronic coordination between the embryonic development and the endometrial status is crucial. The endometrium is a hormonally regulated organ that is nonadhesive to embryos throughout most of the menstrual cycle in humans. Endometrial receptivity refers to a hormone-limited period in which the endometrial tissue acquires a functional and transient ovarian steroid-dependent status allowing blastocyst implantation and therefore pregnancy initiation. Recent findings Our group has developed the endometrial receptivity array (ERA), a customized array based on the expression of 238 genes coupled to a computational predictor capable of diagnosing a functionally receptive endometrium regardless of its histological appearance. Clinical results obtained in our laboratory demonstrate the diagnostic and therapeutic efficiency of the ERA test in patients with implantation failure, allowing the personalization of the optimal day for embryo transfer. Summary To keep improving the global knowledge of endometrial receptivity stage, new high-throughput techniques like RNA-seq or genome-wide association studies will be crucial in the near future. Also the identification of new biomarkers of endometrial receptivity that could be assessed by noninvasive methods has become a challenging goal to help diagnose the endometrial status to increase implantation rates and pregnancy outcomes in patients undergoing assisted reproductive treatments. Copyright © 2015 YEAR Wolters Kluwer Health, Inc. All rights reserved.