Preimplantation genetic screening- the required RCT that has not yet been carried out

The utilization of trophectoderm biopsy combined with comprehensive chromosome screening (CCS) tests for embryonic aneuploidy was recently suggested to improve IVF outcome, however, not without criticisms. The ongoing discussion on the unrestricted clinical adoption of preimplantation genetic screening (PGS) has called for a proper randomized controlled trial (RCT), aiming to further evaluate the cumulative live birth rates (LBRs) following a single oocyte retrieval, utilizing all fresh and frozen embryos. Since this study seems not to appear for various reasons, we present herewith, the hypothetical required RCT based on the hitherto published literature.After implementing data from the hitherto published literature on blastulation and aneuploidy rates, the rate of mosaicism and technical errors and implantation rates/LBRs of non-PGS day-3 and blastocyst and PGS blastocyst, we could clearly demonstrate the superiority of non-PGS embryo (day-3 and blastocyst) transfer over PGS blastocyst transfer, in terms of cumulative LBR (18.2-50 % vs 7.6-12.6 %, respectively).We therefore believe that until the proper, non-hypothetical RCT on the efficacy of this procedure will appear, PGS should be offered only under study conditions, and with appropriate informed consents.