FAILED THAW CYCLES (FTHC) AS A KEY PERFORMANCE INDICATOR (KPI): EVALUATING THE PROGRESS OF FROZEN EMBRYO TRANSFERS (FET) IN USA.

Embryo cryosurvival rate is a recommended KPI to be benchmarked. Lower success rates in FET cycles could be related to ET decisions and freezing procedures, including minimal standards to cryopreserve. We evaluated FThC cycles and related FET outcomes across SART age groups and infertility diagnosis over 6 years. Descriptive review of the SART database included 262,818 FET thawing cycles, 2014-2019 (1st transfer ≥12 months after retrieval, 2nd or later transfers only, limited by database output). Outcomes were: percentage of thaw cycles with no embryos suitable for transfer (FThC), mean number of embryos transferred, and live birth rate (LBR). Regression models adjusting for age and diagnosis estimated the changes in these outcomes over time. Mean increase in thaw cycles was 15.2% per year (32,381 to 57,019, 2014-2019). FThC decreased for all age groups, -0.28% per year (p<0.0001), independent of diagnosis; FThC 2014 to 2019: <35: 1.1% to 0.4%; 35-37: 1.5% to 0.6%; 38-40: 1.5% to 0.8%; 41-42: 2.4% to 1.0%; >42: 3.3% to 2.4% - highest improvement of 61% for ages 41-42. Mean number of embryos transferred decreased from 1.62 to 1.22 (p<0.0001). LBR increased across all age groups by +2.17% per year (p<0.0001). Age ≥41 had over 10% improvement and younger groups had over 5% improvement. LBR also increased for all diagnoses combined by +1.76% per year (p<0.0001), and for individual diagnoses by 1.14–3.53% (all p<0.01), but didn’t reach significance for uterine factors (Table). FThC significantly decreased across all ages and diagnosis, even as FET cycles increased. This likely reflects the evolution of freezing criteria, procedures and clinical decisions positively impacting LBR. Such improvements in FThC and LBR along with fewer embryos transferred may also reflect the impact of PGT and freeze-all. This additional analysis is underway.