ABSTRACT
OBJECTIVE: This study investigated the potential of the slow-developing blastocysts using preimplantation genetic testing-aneuploidy (PGT-A) in patients undergoing frozen-thawed embryo transfer, stratified by age. STUDY DESIGN: A retrospective analysis was performed including a total of 743, the first frozen embryo transfer (FET) cycle with single embryo transfer (SET), who underwent treatment between January 2020 and July 2023 in a single fertility center, XXXX Fertility Center. A total of 743 cycles, in which we performed intracellular sperm injection and freeze all strategy, from 743 patients were included. The patient group was divided into 4 groups as follows: Group 1 (G1), 208 FET on day 5; Group 2 (G2), 177 FET with PGT-A on day 5; Group 3 (G3), 220 FET on day 6; Group 4 (G4), 138 FET with PGT-A on day 6. We also divided into two groups-under 35 years of age and over 35 years of age-and performed the analysis separately for each group. RESULTS: In under 35 years of age groups, there were no significant differences in clinical pregnancy and miscarriage rates in G1 and G2 (67.2% vs 63.8%, NS). Also, G4 had a higher clinical pregnancy rate than G3, but it was not significant (51.8% vs 54.7%, NS). In 35 years or older group, G2 had higher pregnancy rates than G1 and lower miscarriage rates (CPR: 43.3% vs 67.7%, P = 0.001, MR: 22.5% vs 3.4%, P = 0.001). In addition, G4 had a higher pregnancy rate than G3 and lower miscarriage rate (CPR: 31.8% vs. 46.9%, P = 0.003, MR: 22.9% vs 2.2%, P = 0.023). CONCLUSIONS: In ≥35 years group, PGT-A on day 5 and day 6 showed a high pregnancy rate and a low miscarriage rate. Therefore, using PGT-A seems advantageous for patients of an advanced maternal age.