Multinucleation of a sibling blastomere on day 2 suggests unsuitability for embryo transfer in IVF–preimplantation genetic screening cycles

Objective To evaluate the impact of multinucleation of a sibling blastomere of day 2 embryos on the rate of aneuploidy detected by day 3 preimplantation genetic screening (PGS) biopsy and the effect on subsequent implantation and pregnancy rates. Design Retrospective cohort study. Setting University-based IVF center. Patient(s) A total of 141 couples undergoing their first IVF-PGS cycle for idiopathic recurrent pregnancy loss (RPL) or multiple failed IVF implantations. Intervention(s) Biopsy of single-nucleated blastomeres for PGS analysis of chromosomes X, Y, 13, 15, 16, 17, 18, 21, and 22 by fluorescence in situ hybridization. Main Outcome Measure(s) Aneuploidy, implantation, and pregnancy rates. Result(s) PGS revealed an increased incidence of aneuploidy when comparing multinucleated day 2 embryos with single-nucleated embryos (85% vs. 78%; relative risk 0.92 (95% confidence interval 0.84–1.00). Transfer of single-nucleated euploid embryos resulted in clinical pregnancy and implantation rates of 28% and 24%. Transfer of multinucleated euploid embryos resulted in no implantations. Conclusion(s) The presence of multinucleated blastomeres on day 2 of embryo development, 1 day before biopsy, predicts an increase of aneuploidy and poor pregnancy outcomes in IVF-PGS cycles.