Beyond euploidy: the synergistic value of blastocyst morphology in predicting ongoing implantation in advanced maternal age women.

Abstract: This single-centre retrospective study evaluated whether blastocyst morphology remains an independent predictor of euploidy and implantation rates in an advanced maternal age (AMA) population after controlling for chromosomal status. Analysing 1,067 biopsied blastocysts from 308 IVF cycles (269 patients) between October 2021 and December 2022, embryos were graded via the Gardner and Schoolcraft system and categorised into Excellent, Good, Average, and Poor groups. The overall euploidy rate was 33.62%, with blastocysts of the Excellent group exhibiting a significantly higher euploidy rate compared to the Good, Average, and Poor groups (65.38 vs 54.74, 31.46, and 18.79%, respectively; P < 0.001). Logistic regression confirmed that Excellent/Good (odds ratio (OR): 5.60; 95% CI: 4.07-7.71) and Average (OR: 1.98; 95% CI: 1.40-2.81) embryos were significantly more likely to be euploid than Poor embryos. Among confirmed euploid transfers, morphological grade significantly impacted clinical outcomes: Excellent/Good grades yielded an implantation rate of 52.38%, whereas Poor grades yielded only 23.81% (P < 0.05). Multivariate analysis verified that morphological grade is a significant prognostic factor for implantation, independent of ploidy status. In conclusion, euploidy does not equalise implantation potential across all morphological grades in older women. Thus, blastocyst morphology serves as a critical secondary selection tool, suggesting that Poor-grade euploid embryos may harbour non-chromosomal compromises that affect developmental competence. Lay summary: When patients undergo IVF, they often use genetic testing (PGT-A) to select embryos with the correct number of chromosomes, known as 'euploid' embryos. While it is often suggested that genetic normalcy is the most critical factor for success, the importance of an embryo's physical appearance (morphology) in these cases remains a subject of debate. Our study investigated this in women aged 35 or older by analysing over 1,000 embryos and found that, even among those with normal genetics, morphology still plays a vital role. Specifically, genetically normal embryos with poor physical appearances had significantly lower chances of successful implantation compared to high-quality ones. We discovered that the quality of the 'inner cell mass', the part that becomes the baby, is a particularly strong predictor of success. These findings suggest that, for older patients, choosing an embryo based on both genetics and appearance is essential for the best pregnancy outcome.