Elective fertility preservation: a national database study on trends in oocyte cryopreservation and oocyte utilization over a 5- to 7-year follow-up period.

Background: In 2012, oocyte cryopreservation was no longer deemed experimental by the American Society of Reproductive Medicine. Since then, awareness and utilization of planned oocyte cryopreservation have become much more widespread. However, little is known regarding current national trends and the rate of warming and utilization of cryopreserved oocytes.

Objective: To assess national trends in planned oocyte cryopreservation, subsequent oocyte utilization, and outcomes of oocyte warming cycles.

Study design: Retrospective cohort study with data from all patients reported to the Society for Assisted Reproductive Technology Clinic Outcome Reporting System undergoing cryopreservation of autologous oocytes for fertility preservation only between the years 2014 and 2021 and all linked oocyte warming cycles. Statistical analyses were performed using linear regression tests.

Results: The number of patients undergoing planned oocyte cryopreservation has increased exponentially, with 4153 patients in 2014 compared to 16,436 in 2021 (P<.01). There is a decrease in the age of patients undergoing planned oocyte cryopreservation over time, with a mean age of 36.0 years in 2014 compared to 34.9 years in 2021 (P<.01). Subsequent return for utilization of cryopreserved oocytes within a 5- to 7-year follow-up period from planned oocyte cryopreservation cycles occurring between 2014 and 2016 was low, with only 852 patients (5.7%) returning for oocyte warming. The likelihood of returning increased with advancing patient age at the time of oocyte cryopreservation, while the mean time to oocyte warming significantly decreased with increasing patient age at the time of oocyte cryopreservation, except in patients >42 years (P<.01). Of patients who returned for oocyte warming, 78.5% (n=669) obtained a usable embryo, while 21.5% (n=183) had no usable embryos. Of those with usable embryos, 64.2% (n=547) had a fresh embryo transfer, 46.1% (n=393) had embryos for cryopreservation, and only 14.3% of patients (n=122) opted for a freeze-all approach. Of the 393 patients with cryopreserved embryos, 115 (29.3%) returned for a frozen embryo transfer. The cumulative live birth rate of all patients undergoing oocyte warming was 28.9%, with live birth rate decreasing with an increasing age at the time of oocyte cryopreservation.

Conclusion: Since the availability of oocyte cryopreservation reporting for fertility preservation only, planned oocyte cryopreservation has increased exponentially. Mean age at the time of oocyte retrieval has decreased, reflecting interest in the procedure among younger patients, but there has been minimal change in distribution by race/ethnicity and geographic region. Despite the increase in oocyte cryopreservation, return for oocyte warming over a 5- to 7-year follow-up period was low, with a substantial portion of cryopreserved oocytes remaining unused. Patients who were older at the time of oocyte cryopreservation were more likely to return and had a shorter interval between oocyte cryopreservation and warming. Although rates of oocyte warming are low, the outcomes for patients who do return to use cryopreserved oocytes are reassuring. Most patients have a usable embryo after oocyte warming and the live birth rates are reassuring and demonstrate an expected age-related decline. However, given the low return rate, the yield on a per-planned oocyte cryopreservation cycle is very low.