Key messages
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It is unclear whether making an injury to the lining of the womb (uterus) affects the chance of having a baby from IVF. The current evidence shows it has no effect or slightly improves the chance.
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Similarly, it is unclear whether injury to the lining of the womb affects the chance of pregnancy through IVF. The current evidence shows it could either improve, have no effect, or decrease the chance of pregnancy through IVF.
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Injury to the lining of the womb may not affect the chance of having a miscarriage from IVF.
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It is unclear whether one injury compared to two injuries before IVF affects the chance of having a baby, achieving pregnancy, or miscarriage.
What is IVF?
IVF is a fertility treatment for couples who have trouble getting pregnant. In an IVF cycle, eggs are collected from the woman and are combined with sperm in the laboratory to create embryos. Embryos are transferred into the womb in the hope that they will implant. Implantation is the process by which an embryo embeds itself into the lining of the womb; it is the first step toward establishing a pregnancy.
What is endometrial injury (injury to the lining of the womb)?
Endometrial injury is an optional procedure that can be done before an IVF cycle. It involves placing a thin plastic tube into the womb to create a small injury (called a ‘scratch’) in the lining of the womb. Research suggests the chances of implantation may increase if this injury is performed sometime before placing the embryo in the womb.
What did we want to find out?
We wanted to find out whether it is safe and effective to perform endometrial injury (or scratching) in women undergoing IVF/embryo transfer compared to no procedure or a pretend procedure.
What did we do?
We searched for studies investigating the effect of endometrial injury versus no procedure or a pretend procedure on important IVF outcomes, such as live birth and pregnancy. We looked at whether it caused any unwanted effects, including miscarriage, multiple pregnancy, pain, and bleeding.
We also included studies that compared one injury versus two injuries.
We only included high-quality studies (randomised controlled trials). We combined the results from all included studies that were similar enough, and looked at the effect of injury to the lining of the womb on each of the outcomes. We summarised the results of the studies and rated our confidence in the evidence, based on factors such as study methods and sizes.
What did we find?
We included 24 studies (7234 women). The studies were quite different, included different populations of women, and performed the injury in different ways, in terms of the medical instruments used and timing of the procedure relative to the IVF cycle. Many studies were poor quality, which means we are not confident in their results. Therefore, we performed the main analyses using only the higher-quality studies. Of the 24 studies included, we only included eight studies (4402 women) in our main analyses.
It is unclear whether endometrial injury affects the chance of having a baby from IVF. If the chance of having a baby from IVF is usually about 27%, then the chance of having a baby when using endometrial injury before IVF would be between 27% and 32%. Similarly, for pregnancy, the evidence is unclear; if the chance of achieving pregnancy from IVF is about 32%, then the chance of pregnancy when using endometrial injury before IVF is between 31% and 37%. Endometrial injury may not affect the chance of miscarriage from IVF.
The endometrial injury procedure causes mild to moderate pain and a small amount of vaginal bleeding, although this is short-lived.
Two studies (40 women) compared the effect of one injury versus two injuries to the womb before IVF. We have little confidence in the evidence due to concerns of potential bias, small study size, and studies only focused on a specific group of women. Therefore, it is unclear whether one injury compared to two injuries before IVF has an effect on the chance of having a baby from IVF, achieving pregnancy, or miscarriage.
What are the limitations of the evidence?
For many included studies, participants and study staff were aware of which group participants had been allocated to. Also, several studies were not registered adequately, which raised concerns about whether there was bias regarding what outcomes were reported. Some studies showed other signs of potential bias, such as unlikely recruitment rates or inconsistent results reported for different outcomes.
We limited our main analysis to studies without these problems. We also did an analysis that included all studies regardless of their quality, which suggested that endometrial injury could increase the chance of pregnancy and live birth. However, we are less confident in this result because these studies are associated with possible bias.
How up to date is this evidence?
This is an update of a 2021 Cochrane review. The evidence is up to date to December 2025.
Read the full abstract
Implantation of an embryo within the endometrial cavity is a critical step in the process of in vitro fertilisation (IVF). Previous research has suggested 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.
Objectives
To 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 strategy
We 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.
Selection criteria
Randomised controlled trials comparing intentional endometrial injury before embryo transfer in women undergoing IVF, versus no intervention or a sham procedure.
Data collection and analysis
We used standard methodological procedures recommended by Cochrane. Two independent review authors screened studies, evaluated risk of bias and assessed the certainty of the evidence by using GRADE (Grading of Recommendation, Assessment, Development and Evaluation) criteria. We contacted and corresponded with study investigators as required. Due to the high risk of bias associated with many of the studies, the primary analyses of all review outcomes were restricted to studies at a low risk of bias for selection bias and other bias. Sensitivity analysis was then performed including all studies. The primary review outcomes were live birth and miscarriage.
Main results
Endometrial injury versus control (no procedure or a sham procedure)
A total of 37 studies (8786 women) were included in this comparison. Most studies performed endometrial injury by pipelle biopsy in the luteal phase of the cycle before the IVF cycle. The primary analysis was restricted 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 a small reduction, or an improvement (odds ratio (OR) 1.12, 95% confidence interval (CI) 0.98 to 1.28; participants = 4402; studies = 8; I2 = 15%, moderate-certainty evidence). This suggests that if the chance of live birth with IVF is usually 27%, then the chance when using endometrial injury would be somewhere between < 27% and 32%.
Similarly, the effect of endometrial injury on clinical pregnancy is unclear (OR 1.08, 95% CI 0.95 to 1.23; participants = 4402; studies = 8; I2 = 0%, moderate-certainty evidence). This suggests that if the chance of clinical pregnancy from IVF is normally 32%, then the chance when using endometrial injury before IVF is between 31% and 37%. When all studies were included in the sensitivity analysis, we were unable to conduct meta-analysis for the outcomes of live birth and clinical pregnancy due to high risk of bias and statistical heterogeneity.
Endometrial injury probably results in little to no difference in chance of miscarriage (OR 0.88, 95% CI 0.68 to 1.13; participants = 4402; studies = 8; I2 = 0%, moderate-certainty evidence), and this result was similar in the sensitivity analysis that included all studies. The result suggests that if the chance of miscarriage with IVF is usually 6.0%, then when using endometrial injury it would be somewhere between 4.2% and 6.8%.
Endometrial injury was associated with mild to moderate pain (approximately 4 out of 10), and was generally associated with some minimal bleeding.
The evidence was downgraded for imprecision due to wide confidence intervals and therefore all primary analyses were graded as moderate certainty.
Higher versus lower degree of injury
Only one small study was included in this comparison (participants = 129), which compared endometrial injury using two different instruments in the cycle prior to the IVF cycle: a pipelle catheter and a Shepard catheter. This trial was excluded from the primary analysis due to risk of bias. In the sensitivity analysis, all outcomes reported for this study were graded as very-low certainty due to risk of bias, and as such we were not able to interpret the study results.
Authors' conclusions
The 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.
Funding
This 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
