To scratch or not to scratch: that is the question. Based on recent data, the current recommendation regarding endometrial scratching is not to scratch.
Endometrial scratching involves the use of an endometrial biopsy sampler such as a pipelle, which is a straw-like apparatus that is thought to increase the rate of embryo implantation by remodeling the endometrium via inflammatory and immunologic pathways. Although there has been controversy as to whether or not endometrial scratching is effective in improving IVF success rates among women with recurrent implantation failure, there have been some review articles that have shown benefit from this procedure. However, the studies included in these reviews have significant methodologic flaws.
A recent well-designed, large, randomized, multi-center clinical trial by Lensen et al, was published in the New England Journal of Medicine in January 2019. The study included 1364 women who were randomized to an endometrial scratching group or no intervention/control group. Fresh and frozen embryo transfer were included and approximately 25% of the women in the study had a history of 2 or more prior unsuccessful embryo transfers.
In terms of primary outcome, there was no difference in live birth rate between the endometrial scratch group and the control group which did not have intervention. In terms of secondary outcomes, there were no differences between the endometrial scratch and control groups in clinical pregnancy rates (pregnancy visible by ultrasound at 6 weeks of gestation), ongoing pregnancy rates (fetal heartbeat visible by ultrasound at 12 weeks of gestation), multiple pregnancy, ectopic pregnancy, miscarriage, among other outcomes.