Cryopreservation time does not decrease follicular viability in ovarian tissue frozen for fertility preservation

OBJECTIVE: To determine the effect of storage duration on cryopreserved ovarian tissue using fresh and frozenthawed samples. METHODS: Seventeen fertile patients underwent an ovarian biopsy during elective laparoscopic tubal ligation. The tissue sample was divided into three parts: one part was processed fresh (FG), and two were slowly frozen, cryopreserved for 30 (G30) or 180 days (G180), thawed and analyzed. Follicular density, follicular viability, and steroidogenic capacity were assessed. RESULTS: We observed no differences between the groups in follicular density, which was assessed in hematoxylin and eosin-stained tissue sections. A heterogeneous follicular distribution was observed in the parenchyma, with a mean density of 361.3±255.4, 454.9±676.3, and 296.8±269.0 follicles/mm3 for FG, G30 and G180, respectively (p = 0.46). Follicular viability was greater in FG (93.4%) when compared with the cryopreserved tissues (70.8% for G30 (