Endometrial Scratching Effect on Clinical Pregnancy Rates in Patients Undergoing Egg Donor In Vitro Fertilization Cycles: the ENDOSCRATCH Randomized Clinical Trial (NCT03108157)

The potential benefit of endometrial scratching (ES) on embryo implantation is still a controversial subject. At present, the single retrospective study in egg donor IVF cycles concluded that ES has no beneficial effect. Our objective was to determine if there are differences in clinical pregnancy rates (CPR) in egg donor cycles when an ES is performed. This is a randomized controlled trial (RCT) in egg donor IVF patients conducted at ProcreaTec Fertility Center in Madrid. Three hundred fifty-two patients were included in total. One hundred sixty-one patients completed the protocol in group A and 172 patients in group B. Patients allocated to group A received an ES in the luteal phase of the cycle preceding the embryo transfer cycle. Group B patients did not receive any intervention. Primary outcome of this RCT was CPR. Secondary outcomes were implantation (IR), miscarriage (MR), ongoing pregnancy (OPR), multiple pregnancy (MulPR), and live birth rates (LBR). CPR was 104 of 161 (64.6%) in group A and 102 of 172 (59.3%) in group B (RR 1.09, 95% confidence interval (CI) (0.92-1.29); p = 0.378). OPR, MR, MulPR, and LBR were also comparable. No major complications were detected after ES and pregnancy complications were comparable. Our results show that there is no beneficial role of ES in egg donor IVF cycles, considering these patients as the ideal model as they share homogeneous embryo quality and endometrial preparation protocols. This trial was registered on April 5, 2017, as the ENDOSCRATCH trial (NCT03108157).