[Screening of embryos for numerical chromosome abnormalities during in-vitro fertilisation is not useful for application in daily practice].

Preimplantation genetic screening (PGS) is a diagnostic procedure using fluorescence in situ hybridisation to detect aneuploidy in cleavage-stage embryos from in-vitro fertilisation (IVF) before transfer into the uterus. It has been suggested that the use of PGS may improve the effectiveness of IVF in women of advanced maternal age. Recently, a Dutch study was published showing that PGS did not increase but instead significantly reduced the rates of ongoing pregnancies and live births after IVF in women of advanced maternal age. This is in contrast to the results of a comparable study from Belgium indicating that there was no difference in pregnancy rates between IVF with or without PGS. Embryo mozaicism, leading to discordant PGS results in 2 cells from the same embryo, might explain the discrepancy in the results of these studies. PGS should not be applied in IVF until the technique has been further developed.