DOES PREIMPLANTATION GENETIC SCREENING (PGS) IMPROVE IVF OUTCOMES?
A huge controversy has now been brewing in our specialty for quite some time. Quietly, many in vitro fertilization (IVF) centers world-wide introduced over the last few years the use of genetic testing of embryos in attempts to improve pregnancy rates with IVF (primarily in Europe, given the acronym preimplantation genetic screening, PGS, to be differentiated from preimplantation genetic diagnosis, PGD, for the detection of genetic abnormalities in embryos). The basic concept behind PGS appears attractive: Since many normal looking embryos are chromosomally abnormal, in routine IVF, many transferred embryos will be chromosomally abnormal. Since such chromosomally abnormal embryos less likely implant, and if they implant, more likely miscarry, elimination of chromosomally abnormal embryos prior to transfer should improve pregnancy rates and diminish miscarriage rates. Based on this hypothetical model, PGS was widely propagated as a successful tool to improve IVF outcomes. In the enthusi
