A review of, and commentary on, the ongoing second clinical introduction of preimplantation genetic screening (PGS) to r
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REVIEW
A review of, and commentary on, the ongoing second clinical introduction of preimplantation genetic screening (PGS) to routine IVF practice Norbert Gleicher & David H. Barad
Received: 5 September 2012 / Accepted: 27 September 2012 / Published online: 5 October 2012 # Springer Science+Business Media New York 2012
Abstract Purpose Current re-introduction of “improved” preimplantation genetic screening (PGS#2) raises the question whether PGS#2 is ready for routine clinical application. Methods We assessed available evidence via review of published data for years 2005–2012, and review of currently ongoing registered clinical trials, based on searches under appropriate key words in PubMed, MEDLINE, Cochrane Database System Review and Google Scholar and http:// www.ClinicalTrials.gov. In absence of prospective clinical trials, and due to limited available data, individual publications/ongoing studies are assessed. Results PGS#2 offers significant improvements in accuracy of aneuploidy diagnosis over PGS#1. By moving embryo biopsy from day-3 after fertilization (6–8 cell stage) to trophectoderm biopsy at blastocyst stage (day 5–6), PGS#2, however, adds additional co-variables to the analysis of efficacy of the procedure, which have special relevance for women with diminished ovarian reserve (DOR), who usually produce small egg and embryo numbers. Limited
published data, claiming efficacy of PGS#2, as well as ongoing clinical trials, do not consider these additional covariables, do not analyze outcomes by intent to treat and, therefore, have to be considered biased in patient selection. Conclusions Here reached conclusions are based on absence of adequate data rather than affirmative outcome assessments. They, therefore, are subject to change at any future date with generation of significant new data. Premature introduction of PGS#1 caused significant damage to patients. As currently no reliable PGS#2 data are available to suggest improvements in IVF outcomes, to avoid a repeat of the PGS#1 experience, PGS#2 should be considered experimental until data show otherwise. Keywords In vitro fertilization (IVF) . Preimplantation genetic screening (PGS) . Aneuploidy . FISH . Array techniques . Embryo biopsy . Experimental procedure
Introduction Norbert Gleicher and David H. Barad contributed equally to the work. Capsule Though the current re-introduction of preimplantation genetic screening (PGS) involves greatly improved aneuploidy testing of embryos, currently available data do not demonstrate outcome improvements for in vitro fertilization (IVF). Until such data become available, PGS, therefore, should be considered an experimental procedure. N. Gleicher (*) : D. H. Barad The Center for Human Reproduction (CHR) - New York, New York, NY 10021, USA e-mail: [email protected] N. Gleicher : D. H. Barad Foundation for Reproductive Medicine, New York, NY 10021, USA
Only a few years ago, during the initial introduction of preimplantation genetic screening (PGS#1) to in vitro fertilization (IVF), we attempted to warn abou
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