Does endometrial scratching improve live birth rate in IVF cases?

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Endometrial scratching-taking an endometrial-biopsy sample-has been proposed as a way to improve live birth rates with in vitro fertilization (IVF). Some studies have suggested a benefit for the procedure, but they have had limitations including small sample sizes and unclear methods of randomization. New data are now available on endometrial scratching from a large, multicenter, randomized trial. 

The 1364 women in the study, published in The New England Journal of Medicine, were recruited from June 2014 through June 2017 at 13 sites in five countries. All were undergoing IVF (both fresh- or frozen-embryo transfer) and had no recent exposure to disruptive intrauterine instrumentation, such as a hysterectomy. Participants were randomized 1:1 to either endometrial scratching by Pipelle biopsy or to no intervention.  

The live birth rate for the endometrial scratching group was 26.1% versus 26.1% in the control group. There were also no significant differences between the two groups in rates of ongoing, clinical, biochemical, multiple or ectopic pregnancy or miscarriage. In women who had not failed implantation at least twice, no benefit was found for endometrial scratching (estimated interaction odds ratio, 0.63; 95% CI 0.35 to 1.15; P= 0.14). Furthermore, neither the number of days between endometrial scratching and embryo transfer nor reported pain during the procedure were associated with greater odds of livebirth. 

Limitations of the study included lack of blinding, because after randomization, both a participant and the trial personnel were aware of which group the participant was in. Also, the definition of recurrent implantation failure for this trial was two or more previous unsuccessful transfers and did not involve consideration of the stage or quality of the transferred embryos.

Because data on pain and bleeding were captured only in the endometrial scratch group, it was not possible to compare the frequency of these adverse events between groups. Identified strengths of the research were large sample size and minimal attrition. 

The authors said their results indicate that endometrial scratching is not beneficial for women trying to conceive through IVF. They suggest that clinicians not encourage their patients to pursue the procedure before IVF because it resulted in no improvement in live birth rate, exposes women to the potential for pain, and is associated with a cost of approximately $500 and inconvenience.