The initial success rates for oocyte cryopreservation were low due to the fragility of oocytes and their vulnerability to cellular disruption, but new freezing methods have lead to better outcomes. Vitrification protocols use fast cooling rates combined with a higher concentration of cryoprotectant substances to prevent the formation of ice crystals within the oocytes. Ideally, this results in more viable oocytes after warming. This study investigated the utilisation of frozen oocytes in IVF and consequent pregnancy outcomes through a retrospective analysis of fresh and VOT (vitrification oocyte thaw) cycles. Among a diverse population of IVF patients of varied ages and clinical backgrounds using autologous oocytes, oocyte vitrification does not reduce the chances of pregnancy or adversely impact the gestational age and birth weight of babies born. Oocyte vitrification appears to be a viable option for many patients, providing good pregnancy outcomes and allowing the birth of healthy babies for these women.
The results for this project were presented at the 5th congress of the Asia Pacific Initiative on Reproduction 2014 and are currently being prepared for publication.