Fifteen Years of Autologous Oocyte Thaw Outcomes From a Large University-Based Fertility Center

Changes in social norms have resulted in a trend toward motherhood at a later age in the United States. Oocyte preservation (OC) is now a widely used methodology of fertility preservation used to offset the age-related fertility decline related to decreased oocyte quantity and quality. Most patients with cryopreserved oocytes have not yet returned for thaw, which has contributed to a scarcity of thaw data and difficulty when counseling patients about the pregnancy potential from cryopreserved oocytes. There are fears that the predictive models used in these conversations between provider and patient may overestimate the efficacy of OC. This retrospective cohort study aimed to evaluate the pregnancy outcomes following autologous oocyte thaws at a large university-based fertility center. All patients who underwent at least 1 autologous oocyte thaw and embryo transfer at the New York University Langone Prelude Fertility Center before July 1, 2021 were included. Patients were excluded if the OC was performed for a medical indication, due to lack of sperm, in combination with embryos, or as part of a research protocol, or if the patient had a cancer diagnosis or planned to use a gestational carrier. Data regarding OC, oocyte thaw, and embryo transfer were obtained from the electronic medical record. The primary study outcome was final live birth rate (FLBR). Intracytoplasmic sperm injectionwas used to fertilize all oocytes. Data on number of total oocytes, number ofmetaphase 1 oocytes (M1s), metaphase 2 oocytes (M2s), and number of embryos with 2-pronuclear (2PN) fertilization were obtained. Logistic regression was used to adjust for covariates when evaluating the outcome of LB. Atotal of 543 patients undergoing 800OCs, 605 oocyte thaws, and 436 embryo transfer cycles were included. Themedian age at first OC was 38.3 years (interquartile range [IQR], 36.8-39.7), and themedian time between first OC and thaw was 4.2 years (IQR, 2.9-5.6). Overall cryopreserved oocyte survival was 79%, and the rate of embryos 2PN fertilization was 66% of surviving oocytes. The median age at first transfer was 42.8 years (IQR, 41.2-44.5). The 2 most common reasons for thawing embryos and not undergoing transfer were no euploid embryos after PGT (45%) and embryo arrest (27%). The oocyte and M2 survival rates were higher in patients aged 38 to 40 years than in patients aged <38 and >41 years (P = 0.001), whereas patients aged >38 years had more euploid embryos among biopsied embryos (P = 0.0001). The final FLBR per patient was 39%, with patients aged <38 years at first OC having an FLBR of 51%. Multiple logistic regression controlling for age at first OC, cryopreservation duration, and number of M2s thawed found that age at first OC (B = -0.120; adjusted odds ratio [aOR], 0.89; 95% confidence interval [CI], 0.82-0.96; P = 0.004) and the number of M2s thawed (B = 0.038; aOR, 1.04; 95% CI, 1.02-1.06; P = 0.001) were predictive of LB, but cryopreservation duration (B = -0.001; aOR, 1.00; 95% CI, 0.99-1.01; P = 0.76) was not. The results of this study demonstrate that autologous OC is a viable fertility preservation method that results in an LBR of 39%.