Paired Non-inferiority Study Comparing Overture Semi-automated Vitrification System ("DaVitri") to Standard Manual Process for Clinical Pregnancy Outcomes

This study will recruit 260 female recipients (and up to a maximum of 130 donors). This study is a sequel to the protocol CP-DV-000-GEN-003, entitled, "NON-INFERIORITY STUDY COMPARING OVERTURE SEMI-AUTOMATED VITRIFICATION SYSTEM ("DaVitri") TO STANDARD MANUAL PROCESS USING BLASTOCYST RATE AS THE PRIMARY END POINT". Donors will provide informed consent and will be enrolled before egg retrieval. Once the oocytes are retrieved, they will undergo thorough denudation to remove corona cells and will be assessed for maturity. Subsequently, mature MII oocytes exhibiting good morphology, as per the Vienna Consensus, ranging between 12 and 30 in number, will be processed. These oocytes will then be randomly divided into groups comprising 6 to 8 oocytes each. Therefore, from a single donor, 2 to 4 groups can be generated. An identifier will be assigned for each group. One of the groups will be randomly selected. This group will be randomly assigned to DaVitri or Control. The remaining groups will be randomly selected and assigned alternatively to Control and DaVitri groups: Control oocytes will be manually vitrified and placed into cryogenic storage. Test oocytes will be prepared for vitrification using the DaVitri system. Following preparation with DaVitri, test oocytes will be loaded onto a cryogenic device that is placed into cryogenic storage. The same preservation media (Kitazato) will be used to prepare all oocytes. All oocytes will be warmed manually. Survival rate will be recorded following warming. After warming, the oocytes will be fertilized via Intracytoplasmic Sperm Injection (ICSI) with either donor or patient's partner sperm and resulting embryos cultured to blastocyst stage, keeping score of which embryos come from the Test or Control group. Fertilization rate will be recorded. Embryos will be morphologically assessed (according to Gardner grading system) on day 5-6 to determine blastulation rates and embryo quality in both groups. All the embryos will be