Implantation Failure, Etiology, Diagnosis and Treatment

Abstract

Embryonic implantation is a complex interaction between the embryo and the endometrium. Despite great investigative effort this process is still obscure. Contrary to the great advancement in patient care, follicular recruitment, oocyte quality and aspiration, embryo quality, culture and cryopreservation, our understanding of the implantation process did not enhance as much, and the tools to intervene within this process are limited. The implantation of the transferred embryos still remains the major limiting factor in IVF. Here we will review the current literature on the maternal (uterine, hematologic, immunologic and others) and embryonic factors that are associated with repeated implantation failure (RIF) and describe the various therapeutic approaches to cope with them. In addition, we will present our conclusive recommendations on how to investigate and manage RIF based on the literature and our own experience.

Does sequential embryo transfer improve pregnancy rate in patients with repeated implantation failure? A randomized control study

“…Any abnormality attributed to the embryo, the endometrium or the immune system will result in implantation failure. Accordingly, treatment of RIF should be targeted to the abnormality detected with correction of any potential malfunction that led to implantation failure (1,14).…”

Knowing a cross-talk between embryo and endometrium can help to achieve successful pregnancy outcome in recurrent implantation failure

“…1 Or when there is failure of IVF after cumulative transfer of more than 10 embryos of high quality. 2 Pregnancy rate following one cycle of IVF can be as high as 60%. But even in very successful centre, some couples fail repeatedly.…”

Assessment and treatment of repeated implantation failure (RIF)

“…However, there are no formal criteria defining the number of failed cycles or the total number of embryos transferred in these IVF attempts. Accordingly, different fertility centers practicing IVF may use different definitions for RIF [93]. Considering the current success rate of IVF treatments and the mean number of embryos transferred in each cycle, we recommend defining RIF as failure of implantation in at least three consecutive IVF attempts, in which 1-2 embryos of high grade quality are transferred in each cycle.…”

“…Therefore, in assessing RIF, the embryo should be evaluated, with reference to the uterus and its functional endometrium. Accordingly, treatment of RIF should be targeted to the abnormality detected, and the correction of any potential malfunction that might contribute to the failure of implantation [61,93]. Figure 1 represents a clinical approach for assessing and treating RIF.…”