The success of assisted fertilization (ICSI; IVF) is determined by a number of factors, including the patient's age, uterine pathology, stimulation protocols, embryo quality and embryo transfer technique.
For the embryo to implant in the uterus, a normal blastocyst would have to "hatch" and then adhere, penetrate, and eventually invade a well-synchronized endometrium, under the influence of estrogen and progesterone. Recently, a number of locally acting molecules have been discovered such as growth factors, cytokines, matrix metalloproteinases (MMPs), adhesion molecules, components of the extracellular matrix, and elements that mediate the action of steroid hormones on the endometrium.
The Israeli gynecologists were the first to study the effect of endometrial lesions on pregnancy outcomes, even demonstrating a doubling of the percentages of implantation, clinical pregnancies and births, in patients who had undergone endometrial curettage in the cycle immediately preceding the cycle of assisted fertilization. The hypothesis behind these extraordinary results is that the "damage" inflicted on the endometrium could lead to a massive secretion of growth factors and cytokines during the wound healing process, and that these could facilitate embryo implantation. in utero.
More recently, a group of Indian gynecologists set out to test the hypothesis that endometrial damage performed in the cycle prior to the transfer would improve the likelihood of pregnancy in the subsequent IVF cycle in patients who have had previous failures. The patients of the study were chosen from among those who had at least one failed assisted fertilization treatment behind them, who were receptive to ovarian stimulation, with an age not exceeding 37 years. Patients underwent Pipelle endometrial biopsy twice (between 7-10 days - 24-25 days) in the cycle prior to the transfer. The results obtained from this recent study are in line with the Israeli study, leadingpregnancy and birth rates double compared to the control group, specifically: pregnancy rates 32.7% versus 13.7%, birth rates 22.4% versus 9.8%.
These important and authoritative studies therefore demonstrate that clinical birth and pregnancy rates increase significantly after endometrial curettage in the pre-transfer cycle in patients with good quality embryos. This phenomenon could be due to the induced endometrial lesion secondary to a secretion of factors in the healing process which, acting locally, would favor implantation.