Correlation between Morphologic Grading and Euploidy Rates of Blastocysts, and Clinical Outcomes in In Vitro Fertilization Preimplantation Genetic Screening

Background: The standard morphological evaluation has been widely used for embryo selection, but it has limitations. This study aimed to investigate the correlation between morphologic grading and euploidy rate of in vitro fertilization (IVF) preimplantation genetic screening (PGS) and compare the pregnancy rates in young and old ages. Methods: This is a retrospective study using the medical records of patients who underwent IVF procedures with PGS between January 2016 and February 2017 in a single center. The embryo grades were categorized into 4 groups: excellent, good, fair, and poor. Basic characteristics, euploidy rates, clinical pregnancy (CP) rates and ongoing pregnancy rates were analyzed. Results: The excellent group had significantly higher rate of euploid embryos than fair group (47.82% vs. 29.33%; P = 0.023) and poor group (47.82% vs. 29.60%; P = 0.005). When the four groups were recategorized into two groups (excellent and good vs. fair and poor), they also showed significant difference in euploidy rates (44.52% vs. 29.53%; P = 0.002). When the patients were divided into two groups by age 35, the CP rates for those under and over 35 years old were 44.74% and 47.83%, respectively, which showed no significant difference. Conclusion: The significant differences among the euploidy rates of different morphologic embryo grades demonstrated the positive correlations between the morphologic grading of the embryo and the euploidy rate of PGS. Additionally, there was no significant difference between the younger and older patients' CP rates. These findings emphasize the fact that old age patients might benefit from PGS whatever the indication of PGS is.