Endometrial scratching - is a controlled damage to the endometrium using a tool used to biopsy the endometrium. Studies confirm that the procedure may bring benefits in the situation of patients with reccurent implantation failures (Reccurent Implantation Failure). The treatment modifies the activity of the immune system in the uterus by affecting the endometrial cells and changing the secretion of the so-called endometrial cells. growth factors. The so-called local processes of "repair" of damaged tissue may favor the implantation of the embryo in the next cycle. The treatment should be performed in the cycle preceding stimulation in the in vitro program.