Pre-implantation genetic testing in ART: who will benefit and what is the evidence?

• Published in: Journal of assisted reproduction and genetics 2016-10, Vol.33 (10), p.1273-1278
• Main Authors: Vaiarelli, Alberto, Cimadomo, Danilo, Capalbo, Antonio, Orlando, Giovanna, Sapienza, Fabio, Colamaria, Silvia, Palagiano, Antonio, Bulletti, Carlo, Rienzi, Laura, Ubaldi, Filippo Maria
• Format: Article
• Language: English
• Subjects: Blastocyst; Embryo Implantation - genetics; Embryo Transfer - methods; Female; Genetic Testing; Gynecology; Human Genetics; Humans; Infertility, Female; Medicine; Medicine & Public Health; Pregnancy; Pregnancy Rate; Preimplantation Diagnosis - methods; Reproductive Medicine; Reproductive Techniques, Assisted - trends; Review; Vitrification
• ISSN: 1058-0468; 1573-7330
• DOI: 10.1007/s10815-016-0785-2

Pre-implantation genetic diagnosis for aneuploidy testing (PGD-A) is a tool to identify euploid embryos during IVF. The suggested populations of patients that can benefit from it are infertile women of advanced maternal age, with a history of recurrent miscarriages and/or IVF failures. However, a general consensus has not yet been reached.After the clinical failure of its first version based on cleavage stage biopsy and 9 chromosome-FISH analysis, PGD-A is currently performed by 24 chromosome screening techniques on trophectoderm (TE) biopsies. This approach has been clearly demonstrated to involve a higher clinical efficiency with respect to the standard care, in terms of sustained pregnancy rate per transfer and lower miscarriage rate. However, data about PGD-A efficacy calculated on a per intention-to-treat basis, as well as an analysis of its cost-effectiveness, are still missing.TE biopsy is a safe and extensively validated approach with low biological and technical margin of error. Firstly, the prevalence of mosaic diploid/aneuploid blastocysts is estimated to be between 0 and 16 %, thus largely tolerable. Secondly, all the comprehensive chromosome screening (CCS) technologies adapted to, or designed to conduct PGD-A are highly concordant, and qPCR in particular has been proven to show the lowest false positive error rate (0.5 %) and a clinically recognizable error rate per blastocyst of just 0.21 %.In conclusion, there is a sufficient body of evidence to support the clinical application of CCS-based PGD-A on TE biopsies. The main limiting factor is the need for a high-standard laboratory to conduct blastocyst culture, biopsy and vitrification without impacting embryo viability.