Handling and Assessing of Human Oocytes and Blastocysts After Vitrification and Warming

The increasingly widespread use of vitrified human oocytes and embryos by many couples for different indications requires the evaluation of this technique in different scenarios. Thus, vitrification can be assessed in terms of survival rates, subsequent embryo development, implantation success, and live birth rates in IVF cycles using vitrified oocytes or embryos. These endpoints depend largely on the clinical factors of each patient, as well as the harmful effects intrinsic to vitrification. Despite this, many of the best quality oocytes and embryos do not maintain their characteristics when warmed. This problem is accentuated in blastocysts, which need several hours to re-expand and be evaluated. The search for new quality markers together with the development and implementation of AI algorithms to aid embryologists’ decision-making may be the way to overcome these challenges.