Abstract
To establish a new model for the selection of a single blastocyst that has high developmental potential, the relationship between the developmental competence of blastocysts and their oxygen consumption was assessed. The oxygen consumption rate of blastocysts just after thawing was significantly lower than that of non-frozen blastocysts. The oxygen consumption of blastocysts with high developmental competence was restored earlier than that of blastocysts with low developmental competence in spite of the absence of differences in morphology. Our data suggest a new model for the selection of frozen-thawed blastocyst with high developmental competence based on its cellular respiration activity.