The impact of intentional endometrial injury on reproductive outcomes: a systematic review and meta-analysis

Abstract BACKGROUND Endometrial injury is an intentional damage made to the endometrium, usually produced by a Pipelle catheter. Over the last two decades, endometrial injury has been studied to improve implantation rates and decrease the incidence of implantation failure in invitro fertilization (IVF) cycles. Recently, additional studies of endometrial injury, performed not only in patients with implantation failure but also in intrauterine insemination cycles, have been conducted, and the endometrial injury made by hysteroscopy has been researched. The evidence describing the impact of endometrial injury is controversial; therefore, we conducted a systematic review and meta-analysis to examine the issue. OBJECTIVE AND RATIONALE Our objective is to review the research that has been done until now and perform a meta-analysis regarding endometrial injury and its influence on implantation success and pregnancy rates in patients with at least one failed IVF cycle. In particular, we aim to study the efficacy of the procedure and look for confounding factors, such as maternal age, in assessing the efficacy of endometrial injury. SEARCH METHODS The systematic review of the literature was conducted according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) statement. Study protocol can be assessed at PROSPERO International prospective register of systematic reviews (registration number CRD42018092773). Searches were conducted by an experienced research librarian in the following databases: MEDLINE(R) using the OvidSP interface and PUBMED, Embase, Web of Science and Cochrane Library. This review considered for inclusion randomized-controlled trials examining the success of performing local endometrial injury on IVF outcomes in women with previous failed IVF cycles. OUTCOMES Ten studies, comprising a total of 1260 patients, were selected. Overall, when studying the effect of endometrial injury on clinical pregnancy rates (CPRs) and live birth rates (LBRs), higher rates were shown in the endometrial injury group. However, endometrial injury did not significantly improve CPRs and LBRs, when considering sub-group analyses of studies including patients with two or more failed IVF cycles, studies examining older patients or studies which did not include hysteroscopy. There was no significant difference found regarding multiple pregnancy rates, while a handful of studies showed an improvement in miscarriage rates. WIDER IMPLICATIONS Endo