Received January 23, 2017
Accepted June 20, 2017

Objective: Alterations in endometrial receptivity may be involved in etiopathogenesis of endometriosis-related infertility. Literature has suggested that patients with endometriosis present progestin resistance, which could affect embryo implantation. We question the presence of alterations in the expression of progesterone receptor gene (PGR) and genes related to endometrium-embryo interaction regulated by progesterone. This pilot study compared the expression of PGR, HBEGF, ITGAV, ITGB3, and SPP1 genes in eutopic endometrium during the implantation window (IW) of infertile women with endometriosis with that observed in the endometrium of fertile and infertile controls. Methods: In this prospective case-control study, endometrial biopsies were performed during the IW in patients aged between 18 and 45 years old, with regular cycles and without endocrine/systemic dysfunctions, divided into endometriosis (END), infertile control (IC) and fertile control (FC) groups. Total RNA extraction, cDNA synthesis, and gene expression analysis by Real-Time PCR were performed. The size of the difference that our casuistry was powered to detect was evaluated. Results: From the 687 patients who underwent diagnostic videolaparoscopy or tubal ligation at the University Hospital, 130 were eligible. Of these, 32 had endometrial sample collected, with 17 confirmed in the IW. Fifteen samples (5 END, 5 IC and 5 FC) were analyzed. There was no significant difference in the expression of any studied gene. Our sample size allowed us to identify or discard large differences (two standard deviations) among the groups. Conclusion: Endometriosis doesn’t cause large changes in the endometrial expression of PGR, HBEGF, ITGAV, ITGB3 and SPP1 during the IW.