Use of cryopreserved ovarian tissue in the Danish fertility preservation cohort.

Objective To evaluate the use of cryopreserved ovarian tissue in the Danish fertility preservation cohort. Design Retrospective cohort study. Setting University hospitals and fertility clinics. Patient(s) Ovarian tissue cryopreservation (OTC) was performed for 1,186 Danish girls and women from 1999–2020, of whom 117 subsequently underwent ovarian tissue transplantation (OTT). Subgroup 1 included 759 patients with a follow-up period of >5 years. Out of these, OTT rates were further analyzed for those patients who were alive and aged >24 years in July 2020 (subgroup 2; n = 554). Intervention(s) OTC and OTT. Main Outcome Measure(s) OTT, death, donation of tissue. Result(s) In subgroup 1, 14% of the patients had undergone OTT, 18% had died, 9% had donated their tissue for research, and 59% still had their tissue stored. In subgroup 2, 19% had undergone OTT and for most diagnoses the OTT rates ranged from 15% to 22% with benign hematologic diseases having the highest OTT rate (35%). On the basis of the entire cohort, stratified age analysis indicated that women aged ≥30 years at OTC were more likely to return for OTT than women aged 18–29 years at OTC; mean storage times were 3.7 and 3.6 years, respectively. Only 4% of the girls aged Conclusion(s) The OTT rates depended on the diagnosis, age at OTC, and follow-up time. Specific criteria are needed for reporting and comparing OTT rates. Six out of 10 patients still had their cryopreserved tissue stored and longer follow-up is needed, especially for younger girls.