The effect of endometrial injury on pregnancy rate in frozen-thawed embryo transfer: A randomized control trial

Abstract

Implantation failure is one of the most important factors limiting success in IVF treatment (1). Embryo implantation is a critical process of embryonic attachment to endometrium and subsequent invasion into uterine wall (2). Uterus is receptive during mid-secretory phase (days 19-23) of menstrual cycle, which is known as window of implantation (2). Implantation of embryo is a multiple process including several cytokines and growth factors, along with a dialogue between embryo and uterine endometrium (3). Numerous factors have been contributed increasing embryo implantation success (4). Majority of trials have demonstrated favorable effect of endometrial injury on implantation success rate, especially in women with recurrent implantation failure (RIF), while some studies failed to detect any benefit (5-13). Kalma et al suggested that “local injury to endometrium causes significant changes in pattern of expression of genes related to implantation” (14). Gnainsky et al reported that “endometrial injury induces an inflammatory reaction which favors implantation” (15). Dendritic cells, natural killer cells and macrophages are employed to local injury and increased amounts of cytokines, chemokines and growth factors are secreted, thus resulting in successful implantation (15, 16). To our knowledge, there has not been enough research due to the effectiveness of endometrial injury prior to frozen-thawed embryo transfer (FET) cycle. The purpose of our trial was to explore whether endometrial injury in luteal phase prior to FET cycle would improve pregnancy outcomes?

A Randomized Trial of Endometrial Scratching before In Vitro Fertilization

“…14 The results from multiple previous trials have been inconsistent but have generally favored endometrial scratching in women undergoing IVF. 8,[22][23][24][25][26] Many of these studies were small and underpowered or suffered from a high risk of bias, such as lack of concealment of trial-group assignments (which is known to be associated with exaggeration of treatment effect) 27,28 and other biases (e.g., stopping early for a positive effect). 8 The current trial had a large sample size, concealed trial-group assignments to limit the potential for selection bias, and had minimal attrition; four women withdrew from the trial, and the pregnancy outcome of only one other participant is unknown.…”

Systemic administration of bone marrow‐derived cells leads to better uterine engraftment than use of uterine‐derived cells or local injection

“…In this study, we used a mouse model consisting of a mild endometrial injury, which did not result in unwanted uterine adhesions, but was sufficient to stimulate increased recruitment of donor cells to the uterus. This models therapeutic uterine injury (endometrial scratch), which has been increasingly utilized in an attempt to improve endometrial receptivity and implantation in patients with recurrent implantation failure and/or thin endometrium [20,21]. Following uterine injury and BMDCs/UDCs injection, GFP + cells were detected in the uterus of the treated mice.…”

“…Clinically, in infertile women, therapeutic uterine injury has been increasingly utilized in an attempt to improve endometrial receptivity and implantation in patients with recurrent implantation failure and/or thin endometrium [20,21]. We have previously shown that ischaemic/reperfusion injury provides a strong stimulus for homing and engraftment of BMDCs into the uterus [18], and it has been suggested that one of the mechanisms by which uterine injury may improve endometrial receptivity is via increasing recruitment of BMDCs to the endometrium.…”

Outcome of Different Endometrial Preparation Protocols Prior to Frozen-Thawed Embryo Transfer on Pregnancy Outcomes in Women with Repeated Implantation Failure

“…15 Decidualization of the endometrium could be initiated by ES, thus increasing the probability of implantation of a replaced embryo. 16 Furthermore, inflammatory and immune processes could be influenced by ES, leading to the promotion of embryo implantation. [17][18][19][20] In addition, studies have demonstrated that the use of gonadotropin-releasing hormone (GnRH) prior to FET could regulate the expression of the enzymes and cytokines, which play a directly impact on endometrial receptivity markers.…”