Fifteen years of autologous oocyte thaw outcomes from a large university-based fertility center

Abstract

Objective: To review the outcomes of patients who underwent autologous oocyte thaw after planned oocyte cryopreservation.

Design: Retrospective cohort study.

Setting: Large urban university-affiliated fertility center.

Patient(s): All patients who underwent ≥1 autologous oocyte thaw before December 31, 2020.

Intervention(s): None.

Main outcome measure(s): The primary outcome was the final live birth rate (FLBR) per patient, and only patients who had a live birth (LB) or consumed all remaining inventory (cryopreserved oocytes and resultant euploid/untested/no result embryos) were included. The secondary outcomes were laboratory outcomes and LB rates per transfer.

Result(s): A total of 543 patients underwent 800 oocyte cryopreservations, 605 thaws, and 436 transfers. The median age at the first cryopreservation was 38.3 years. The median time between the first cryopreservation and thaw was 4.2 years. The median numbers of oocytes and metaphase II oocytes (M2s) thawed per patient were 14 and 12, respectively. Overall survival of all thawed oocytes was 79%. Of all patients, 61% underwent ≥1 transfer. Among euploid (n = 262) and nonbiopsied (n = 158) transfers, the LB rates per transfer were 55% and 31%, respectively. The FLBR per patient was 39%. Age at cryopreservation and the number of M2s thawed were predictive of LB; the FLBR per patient was >50% for patients aged <38 years at cryopreservation or who thawed ≥20 M2s. A total of 173 patients (32%) have remaining inventory.

Conclusion(s): Autologous oocyte thaw resulted in a 39% FLBR per patient, which is comparable with age-matched in vitro fertilization outcomes. Studies with larger cohorts are necessary.

Keywords: Egg freezing; assisted reproductive technology; fertility preservation; oocyte cryopreservation; oocyte thaw.