ABSTRACT
INTRODUCTION It has been nearly 30 years since the birth of the rst child conceived through the fertilization of a frozen human metaphase II (MII) oocyte.1 Within the last decade, success rates and implementation of oocyte vitrication have increased dramatically. ere remains, however, room for improvement. For example, why do oocytes from 10% to 20% of donors in a given donation cycle fail to tolerate the cryopreservation procedure? What negative impact does vitrication have on oocyte physiology that results in a much sharper age-related decline in clinical outcome compared to fresh oocytes?
