AI-based embryo ranking can match or improve traditional assessments but cannot predict an aneuploid chromosomal constitution.

OBJECTIVE: To evaluate whether AI-based blastocyst ranking tools can outperform traditional non-invasive assessments in prioritizing euploid embryos for transfer. DESIGN: Retrospective single-center cohort study. SUBJECTS: The study included 786 PGT-A cycles performed between 2013 and 2020 following embryo culture in a time-lapse incubator (TLI). The analysis focused on 279 cycles producing ≥3 blastocysts of which ≥1 euploid and ≥1 aneuploid embryo. EXPOSURE: Blastocyst ranking was conducted through: (i) static morphology based on Gardner's score (control; embryologists-assigned scores from 1 [AA] to 9 [CC]), (ii) random guessing, (iii) Gardner's score plus morphodynamic parameters (time of expanding blastocyst [tEB] and embryo area at tEB in μm2), and (iv) two versions of a commercially-available AI model. The coefficient of variation (CV=SD/mean) within each cohort of blastocysts was then calculated to estimate the morphological variability perceived by each method among sibling embryos, and its association with ranking accuracy was investigated. MAIN OUTCOME MEASURES: Accuracy in prioritizing euploid blastocysts within cohorts of sibling embryos, assessed by the proportion of cycles in which a euploid embryo was ranked first, and association between intra-cohort CV and ranking performance. RESULTS: AI model version-2 showed the highest rate of correctly prioritized euploid blastocysts (68%), followed by morphodynamic assessment (64%), AI model version-1 (62%), Gardner's score (58%) and random guessing (44%). Larger intra-cohort CVs for Gardner's scores were positively associated with prioritization of euploid embryos. No such associations were observed with AI-based CVs. CONCLUSION: AI-powered tools can match or slightly improve traditional non-invasive assessments. However, no blastocyst ranking strategy based on morphology/morphodynamics may prevent aneuploid embryos from being prioritized, even in presence of euploid siblings.