Preimplantation genetic screening outcomes are associated with culture conditions.

BACKGROUND: Although preimplantation genetic screening (PGS) is widely offered, there are contradictory reports on the clinical merit of this procedure. Any gain from embryo selection following aneuploidy screening must significantly outweigh the impact of the procedure. Variability of technical expertise in embryo biopsy, blastomere fixation, fluorescence in situ hybridization analysis, along with suboptimal laboratory quality control and inappropriate patient selection may impact PGS outcomes. METHODS: To investigate such effects, a total of 1508 stimulated in vitro fertilization (IVF) cycles were retrospectively analysed. During 2004, a significant change was made to the embryo culture media used. Clinical outcomes from cycles with PGS were compared prior to and after the change in media and compared with matched controls not utilizing PGS during the same period. RESULTS: Clinical PGS success rates were found to improve following the media change. For patients aged less than 40, clinical outcomes following PGS were significantly lower than those without PGS prior to the change, but became equivalent after the change. For patients >or=40 years and