P-098 Impact of low-lactate culture medium on embryo development and euploidy rates in sibling oocytes

Abstract Study question Does low-lactate culture medium have any effects on embryo development and the euploidy rates of blastocysts? Summary answer Low-lactate culture medium appears to accelerate embryo development, resulting in a higher yield of Day 5 usable blastocysts in both age groups. What is known already Low-lactate culture medium have been shown to reduce stress and improve metabolic efficiency during embryo development. Study design, size, duration A total of 183 Intracytoplasmic Sperm Injection (ICSI) cycles from March 2024 to September 2024 were included in this study. Participants/materials, setting, methods Following ICSI, 2552 sibling oocytes were randomly assigned to two culture media: low-lactate (Group 1) or standard-lactate (Group 2) culture medium. The embryos were cultured to the blastocyst stage and categorized according to modified Gardner grading system: excellent (AA), good (AB, BA), fair (BB) and poor (BC, CB, CC). 514 blastocysts underwent trophectoderm biopsy for Pre-implantation Genetic Testing for Aneuploidy (PGT-A), while 649 blastocysts were vitrified without PGT-A. Main results and the role of chance Group 1 exhibited significantly higher Day 5 Blastocyst Utilization Rate (D5 BUR) (48.9% vs. 36.6%, p < 0.05) and Total BUR (TBUR) (64.8% vs. 57.6%, p < 0.05) compared to Group 2. This significant improvement in D5 BUR and TBUR also observed in embryos from both age groups, <38 and ≥38. The euploidy rates was marginally higher in Group 1 (23.3%) compared to Group 2 (18.5%), though this difference was not statistically significant. No difference was observed in the aneuploidy rates (37.3% vs. 37.0%) between the two groups. Although Group 1 demonstrated better D5 BUR, TBUR, and euploidy rates, the excellent-quality blastocyst rates (13.8% vs. 19.6%, p < 0.05) was significantly lower than that of Group 2. Limitations, reasons for caution The number of blastocysts that underwent PGT-A was small in this study, which may impact the statistical power of the analysis of euploidy rates. Further research into implantation and live birth rates is needed to assess the clinical outcomes of low-lactate culture medium. Wider implications of the findings The increased TBUR and euploidy rates in low-lactate culture medium may provide patients with more blastocysts available for embryo transfer. This could reduce the number of IVF cycles required for a successful pregnancy, thereby lowering overall costs for patients. Trial registration number No