ASRM ABSTRACTS: More evidence for Day 5 biopsy for PGS for chromosomes

This is one of a series of news items from abstracts of studies presented at the Annual Meeting of the American Society for Reproductive Medicine as complied by Dr. David Meldrum, Scientific Director of Reproductive Partners. We appreciate the enormous amount of work it takes to compile and comment on these abstracts.


Over the past several years preimplantation genetic screening (PGS) for chromosomes has evolved to using biopsies from Day 5 embryos rather than Day 3 embryos. A study reported at ASRM-2012 reinforces the wisdom of that change.

Forty-five embryos found to be aneuploid (abnormal chromosome configuration) on Day 3 by 23 chromosome SNP array were fully reevaluated on Day 5. 64% of those 45 embryos had euploid (normal chromosome configuration) inner cell masses (fetal portion of the embryo). No mosaicism (variety of chromosome configurations) was detected. This study definitively establishes that embryos self-correct, with aneuploid blastomeres (cells) likely failing to divide and degenerating.

Together with the adverse effect found for Day 3 biopsy, findings such as this indicate that Day 3 biopsy for aneuploidy is inappropriate.