Endometrial injury in women undergoing in vitro fertilisation (IVF).

rationaleImplantation of an embryo within the endometrial cavity is a critical step in the process of in vitro fertilisation (IVF). Research suggests that endometrial injury (also known as endometrial scratching), defined as intentional damage to the endometrium, can increase the chance of pregnancy in women undergoing IVF. The procedure involves placing a thin plastic tube into the uterus to create a small injury (called a 'scratch') in the lining of the womb. This is an update of a 2021 Cochrane review.

objectivesTo assess the effectiveness and safety of endometrial injury performed before embryo transfer versus no procedure or a sham in women undergoing in vitro fertilisation (IVF) including intracytoplasmic sperm injection (ICSI) and frozen embryo transfer. SEARCH

methodsWe searched CENTRAL, MEDLINE, Embase, PsycInfo, CINAHL, LILACS, and Epistemonikos to 11 December 2025. We also handsearched two trial registries to 3 September 2024, and checked the references of relevant studies. ELIGIBILITY CRITERIA: Randomised controlled trials (RCTs) comparing intentional endometrial injury before embryo transfer in women undergoing IVF, versus no intervention, a sham procedure, or a different frequency of the injury (i.e. one injury versus two injuries). There was no restriction on the language or date of the studies. OUTCOMES: The outcomes of interest were live birth, clinical pregnancy, miscarriage, and adverse effects (such as pain, bleeding, and multiple pregnancy). RISK OF BIAS: We assessed the risk of bias using the Cochrane risk of bias assessment tool, RoB 1. Additionally, we used the TRACT checklist, an integrity tool, to help identify any other potential sources of bias. We documented any concerns identified through the TRACT checklist in the characteristics of included studies. SYNTHESIS

methodsWe used standard methodological procedures recommended by Cochrane. Two review authors independently screened studies, extracted data from included studies, evaluated the risk of bias, and assessed the certainty of the evidence by using GRADE criteria. We contacted and corresponded with study investigators as required. Due to the high risk of bias associated with many included studies, we restricted the primary analyses of all review outcomes to studies at a low risk of bias for selection bias and other bias. We then performed sensitivity analyses, including all studies. INCLUDED STUDIES: We included a total of 24 RCTs with 7234 women. SYNTHESIS OF

resultsEndometrial injury versus control (no procedure or a sham procedure) We included a total of 22 studies (7194 women) in this comparison. Most studies performed endometrial injury by pipelle biopsy in the luteal phase of the cycle before the IVF cycle. We restricted the primary analysis to studies at low risk of bias, and included eight studies. The effect of endometrial injury on live birth is unclear as the result is consistent with no effect or an improvement (odds ratio (OR) 1.12, 95% confidence interval (CI) 0.98 to 1.28; I AUTHORS'

conclusionsThe effect of endometrial injury on live birth and clinical pregnancy amongst women undergoing IVF is unclear. The results of the meta-analyses are consistent with an increased chance, no effect, and a small reduction in these outcomes. We are therefore uncertain whether endometrial injury improves the chance of live birth or clinical pregnancy in women undergoing IVF. Endometrial injury may result in little to no difference in chance of miscarriage. The conclusion of the current review did not change from the previous review.

fundingThis review did not receive any specific funding. REGISTRATION: Protocol (2007) DOI: 10.1002/14651858.CD009517 Review (2012) DOI: 10.1002/14651858.CD009517.pub2 Review (2015) DOI: 10.1002/14651858.CD009517.pub3 Review (2021) DOI: 10.1002/14651858.CD009517.pub4.