Current Approach to Recurrent Implantation Failures: Review

Abstract

Copyright © 2017 by Türkiye Klinikleri. Recurrent implantation failure (RIP) is defined as the lack of clinical pregnancy despite the t ransfer of at least 3 fresh embryos or 4 good quality embryos in a freeze-thaw cycle under the age of 40. A successful implantation requires an embryo in blastocyst stage, a receptive endometrium and an efficient interaction between embryo and endometrium. Chromosomal abnormalities, damaged sperm DNA, over-thickened zona pellucida, improper culture media and poor embryo quality are embryologic factors considered in the etiology of RIP. Assisted hatching in select patients, blastocyst transfer and providing optimal culture media might improve the rates of implantation and clinical pregnancy. While preimplantation genetic diagnosis does not seem to improve pregnancy rates, novel alternative approaches such as comparative genomic hybridization and single nucleotide polimorphysm analysis enable us perform a broader genomic screening. Assessing the embryo by using newer techniques like time-lapse imaging technology may prove beneficial in detecting the embryo with the highest potential for implantation. Uterine fibroids, endometrial polyps, congenital abnormalities of the uterus and intrauterine adhesions are preceding uterine factors in the etiology of RIP. Adenomyosis and endometriosis should also be kept in mind for a possible etiology. Potential uterine problems require an ultrasonographic and hysteroscopic evaluation. If a hydrosalpinx is suspected, the patient must be evaluated with a hysterosalpingography (HSG) and a diagnostic laparoscopy can be performed. In case there is a hydrosalpinx, proceeding to a salpingectomy may improve the rates of implantation and clinical pregnancy. A new tool, endometrial receptivity array helps in seizing the implantation window and yields promising results by performing individualized embryo transfer in RIP patients. In recent years, trombophilias and immunological causes also became popular areas of research and immunologic and anti coagulant therapies are used frequently. However, empirical therapies are not to be used in routine daily practice before these therapies are supported by randomized controlled trials. In future, endometrial gene therapies, use of intrauterine adhesion molecules and more developed embryo cultures will provide new opportunities.