The effect of delayed processing on ovarian tissue stored for fertility preservation

BackgroundOvarian tissue cryopreservation (OTC) is important for fertility preservation and conservation. Delay in OTC may be required for transport or workflow management, however little is understood about the effect of processing delay on the tissue. ObjectiveTo determine whether a delay of 24-48 hours to OTC affects primordial follicle (PF) health. MethodsOvaries (n=6 sheep) were processed immediately or after storage at 4{degrees}C (24h, 48h). Tissue was fixed fresh, after cryopreservation or 10-day xenotransplantation. Morphological assessment of follicle health and development was performed. FindingsA total of 1541 follicles were analysed. A 24h processing delay did not impact PF health in fresh or cryopreserved tissue. In fresh tissue a 48h delay had an adverse effect on follicle health (OR=2.47, 95% CI 1.29-4.71). Interestingly, a 48h delay resulted in cryopreserved tissue being less likely to be graded as unhealthy compared to control (OR=0.56, 95% CI 0.36-0.87). There was no difference in PF health or development across groups following xenotransplantation. ConclusionOvarian tissue can be stored for up to 48 hours prior to cryopreservation with no net impact on PF health.