Overnight hypothermic transportation of ovarian tissue prior to cryopreservation in a centralized cryobank of the FertiPROTEKT network.

RESEARCH QUESTION: Does overnight hypothermic transportation (ONT) of ovarian tissue prior to cryopreservation enable feasible implementation in routine practice without negatively impacting clinical outcomes, thus providing location-independent access to ovarian tissue cryopreservation?

DESIGN

Retrospective analysis at a university fertility centre/centralized cryobank (UniKiD/UniCareD) in collaboration with surgical centres of the FertiPROTEKT network. Ovarian tissue was either processed and cryopreserved immediately (≤2 h) after retrieval or transported overnight (4-8°C, ≤24 h) in histidine-tryptophan-ketoglutarate medium prior to cryopreservation, termed the 'ONT (-)' and 'ONT (+)' groups, respectively. Clinical outcomes following 60 transplantations in 51 women were compared according to transport modality, including sensitivity analyses adjusting for potential confounders.

RESULTS

The clinical pregnancy and live birth rates (CPR and LBR, respectively) showed numerical trends favouring the ONT (+) group, whereas the endocrine activity restoration (EAR) rate was comparable between the groups; none of these differences reached significance. The per-patient results [ONT (+) group versus ONT (-) group] were as follows: EAR rate was 94.1% versus 93.8% (OR 1.07, 95% CI 0.02-22.0); CPR was 42.9% versus 25.0% (OR 2.22, 95% CI 0.53-11.35); and LBR was 40.0% versus 25.0% (OR 1.97, 95% CI 0.47-10.14). Per-transplantation results [ONT (+) group versus ONT (-) group] were as follows: EAR rate was 90.2% versus 94.4% (OR 0.55, 95% CI 0.01-6.12); CPR was 52.4% versus 27.8% (OR 2.81, 95% CI 0.77-11.95); and LBR was 40.5% versus 27.8% (OR 1.75, 95% CI 0.47-7.48). Sensitivity analyses did not identify significant associations.

CONCLUSIONS

ONT of ovarian tissue appears feasible in routine practice. No significant differences were detected between study cohorts, although the study is underpowered to exclude clinically meaningful differences. Standardized transport protocols may support centralized cryobanking within fertility preservation networks, expanding access where on-site cryopreservation of ovarian tissue is unavailable.