Objective: To evaluate the association among embryonic morphological parameters, clinical factors and euploid blastocyst formation.
Methods: This prospective cohort study included 422 blastocysts from 135 patients who had undergone preimplantation genetic analysis after intracytoplasmic sperm injection (ICSI).
Results: Of 422 blastocysts, 200 (47.4%) were euploid and 222 (52.6%) aneuploid. Women aged older than 38 years were more likely to develop aneuploid embryos (OR: 3.4, CI: 2.2-5.4, p<0.001). Poor ovarian reserve (OR: 3.3, p<0.001), increased male age (39.0 versus 40.7, p=0.019), and decrease in sperm percentage with normal morphology (2.5% vs. 1.9%, p=0.047) were associated with aneuploidy. Type C trophectoderm (TE) and type C inner cell mass were associated with a high risk of embryo aneuploidy, with OR of 4.1 (CI: 2.2-7.7, p<0.001) and 1.7 (CI: 1.01-3.0, p=0.048), respectively. Logistic regression analysis revealed maternal age and type C TE as the main risk factors for aneuploidy. Among combinations of factors, the best marker for the risk of aneuploidy was maternal age older than 38 years, combined with a type-C embryo with trophectoderm, which showed a positive predictive value of 88.6% and a specificity of 97.5%.
Conclusions: Trophectoderm and type-C inner cell mass are the main embryo risk factors for aneuploidy, explaining approximately 71% and 60% of the risk, respectively. Among clinical factors, advanced maternal and paternal age (older than 38 and 36 years, respectively), antral follicles (<5), and a low percentage of sperm with normal morphology increased the risk of embryonic aneuploidy.
Keywords: PGT-A; aneuploidy; blastocyst; inner cell mass; trophectoderm.