Oocyte Cryopreservation: A 9-Year Single-Centre Experience

Oocyte cryopreservation (OC) has increased in recent years; however, there is a paucity of published data on the use of cryopreserved oocytes and associated outcomes.

A retrospective review of 748 OC cycles between 2013 and 2022 at a private fertility centre was performed. Outcome parameters for oocyte retrieval cycles were reviewed. For patients who returned for oocyte disposition, outcomes subsequent to oocyte re-warming, fertilization, and transfer were analyzed.

There were 748 OC cycles (653 elective and 95 non-elective) in 646 patients (556 elective and 90 non-elective). Patients were older at the time of freezing in the elective oocyte group compared with the non-elective group (36.5 vs. 28.8 y; P < 0.001). Sixty-five patients returned to warm and fertilize their oocytes (50 in the elective group and 15 in the non-elective group). The survival rate for warmed oocytes was 76.1% (541/711), and 66.2% of surviving oocytes were successfully fertilized, and 39.1% reached blastulation. Twenty-three patients underwent embryo transfers (10 after preimplantation genetic testing for aneuploidy), with 15 patients having at least 1 delivery or ongoing pregnancy.

To date, this is the largest published experience with OC in Canada. OC can lead to successful live births but does not guarantee a viable outcome for all patients. In this study, most patients with vitrified oocytes had not returned for disposition, so long-term follow-up is still required to verify the efficacy of OC.