Embryo Ploidy in Women of Different Age Groups Depending on the Comprehensive Assessment of Morphokinetic Parameters KIDScoreD5 v3.2.

Background: The identification of non-invasive markers for selecting the most promising embryo is extremely important today. Morphological assessment is the basic criterion for embryo evaluation in in vitro fertilization (IVF) cycles. However, data on the correlation between embryo morphology, euploidy, and implantation potential are conflicting. With the advent of time-lapse incubators, it has become possible to assess morphokinetic parameters of embryo development and to use them for predicting both ploidy and implantation potential. Based on the morphokinetics of day 5–6 embryos, the computer software of time-lapse incubators provides an automated assessment of embryo implantation potential (KIDScoreD5). This algorithm was developed taking into account the currently known morphokinetic parameters most significant for embryo implantation: cleavage uniformity, blastocyst formation time, and the quality of the inner cell mass and trophectoderm. KIDScoreD5 allows ranking of embryos, which is particularly relevant when several embryos with similar morphology are available. Objective: To evaluate the relationship between KIDScoreD5 and embryo ploidy, and to assess the effectiveness of KIDScoreD5 in predicting embryo ploidy in patients of different age groups. Materials and methods: A retrospective analysis was performed on 1124 embryos with known ploidy obtained from 418 patients undergoing infertility treatment at the Skyfert Clinic in St. Petersburg from January 1, 2021, to March 31, 2025. The mean KIDScoreD5 score of day 5 and day 6 embryos that underwent PGT-A was assessed in two age groups: under 37 years and 37 years and older. The Mann-Whitney test was used for group comparisons. Spearman’s rank correlation coefficient was calculated to assess the relationship between quantitative variables. ROC analysis was used to evaluate the predictive quality of individual parameters and of our developed model for calculating the probability of embryo euploidy. Binary logistic regression was used to assess the relationship between maternal age, KIDScoreD5 score, embryo developmental day, and embryo ploidy. Results: The frequency of euploid embryos decreased significantly with increasing maternal age starting from 37 years (p < 0.0001), based on which patients were divided into two age groups: under 37 years and 37 years and older. The frequency of euploid embryos differed significantly between the two age groups (60.1 and 30.4%, respectively, p < 0.0001) and was also significantly lower in day 6 embryos compared with day 5 embryos (32.3 and 46.8%, respectively, p < 0.0001). KIDScoreD5 scores were significantly higher in euploid embryos, regardless of maternal age and embryo developmental day (p < 0.0001). The correlation between KIDScoreD5 of euploid embryos and maternal age was not significant (p > 0.05). ROC analysis showed that KIDScoreD5 is a significant predictor of ploidy of satisfactory quality, regardless of maternal age and embryo developmental day. Binary logistic regression showed that maternal age and KIDScoreD5 score are independently associated with embryo euploidy (p < 0.0001). Specifically, with each one-year increase in age, the probability of euploidy decreases by 16.6%, while with each one-point increase in KIDScoreD5 score, the probability increases by 33%. Based on these data, a formula was derived for calculating the probability of embryo euploidy considering maternal age and KIDScoreD5 score. ROC analysis showed good predictive quality of the obtained model: AUC 0.732 (0.703:0.761). Conclusions: KIDScoreD5 can serve as an additional tool for embryologists in selecting embryos for PGT-A, helping to reduce the financial burden on patients and the time to embryo transfer after PGT-A. A prospective study is needed to validate our model for predicting embryo euploidy based on KIDScoreD5 and maternal age.