Respiratory Activity of Single Blastocysts Measured by Scanning Electrochemical Microscopy: The Relationship between Pre-Freezing and Post-Warming

Abstract: The aim of this retrospective study was to investigate the relationship between the oxygen consumption rate of blastocysts before freezing and their viability after warming with respect to their re-expansion and blastomere loss after warming. A total of 41 blastocysts from 29 in vitro fertilization (IVF) treatment cycles, that were not scheduled for cryopreservation for the next cycle, were examined. Good quality blastocysts were defined those having as less than 20% of blastomere loss, and rapid re-expanded blastocysts were defined those having as more than 50% blastocoel re-expansion during post-warming culture of 2 h. We evaluated the oxygen consumption rates before freezing and after warming as well as their relationship with the morphological features of good-quality and rapid re-expanded blastocysts during the post-warming culture. Good-quality blastocysts had a significantly higher oxygen consumption rate after warming than damaged blastocysts; furthermore, rapid re-expanded blastocysts h...