Pre‐implantation genetic testing for aneuploidy: the past, present and future

Abstract

Key content Embryonic aneuploidy is often found in women undergoing assisted reproduction and is a common cause of poor outcomes, particularly in women of advanced maternal age and those with recurrent miscarriage and repetitive implantation failure. The aim of pre‐implantation genetic testing for aneuploidy (PGT‐A) is to select the most competent embryo for transfer, thus improving reproductive outcome. Initial PGT‐A techniques failed to show an improvement in delivery rates and, in some trials, demonstrated inferior outcomes; however, advances in technology, combined with robust culture media and vitrification techniques, have significantly improved outcomes. Recent debate has argued for the increased clinical application of PGT‐A, particularly in women of advanced maternal age; we provide an overview of PGT‐A, including its past and associated limitations, the evolution in technology and latest outcomes, and address potential future implications. Learning objectives To understand the rationale behind the use of PGT‐A. To review the evidence against and in favour of PGT‐A. To understand the new techniques being used and how these have led to emerging evidence in favour of PGT‐A. Ethical issues Risk of damage to embryos during biopsying process. PGT‐A may result in either no embryos available for transfer or only embryos displaying mosaicism being available to transfer, with little long‐term data on the outcomes of transferring mosaic embryos. PGT‐A increases the cost of an already expensive treatment.