Comparison of a commercial trehalose-based and laboratory-prepared sucrose-based vitrification solution for human blastocyst cyopreservation: effects on embryological and clinical outcomes

Abstract Background Sucrose and trehalose are commonly used as non-permeating cryoprotectants in cryopreservation, primarily due to their ability to increase extracellular osmolality, which promotes cellular dehydration and minimizes intracellular ice formation. While the effects of these cryoprotectants on clinical outcomes in human oocytes and sperm have been extensively studied, their roles in the vitrification of human embryo remain underexplored. The optimization of cryoprotectants is crucial for improving pregnancy outcomes in assisted reproductive technology (ART), particularly in in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) cycles, where surplus embryos or embryos unsuitable for fresh transfer are cryopreserved due to clinical considerations. This study aimed to compare the efficacy of sucrose-based and trehalose-based vitrification solutions for human blastocyst cryopreservation and to evaluate their impact on embryological and clinical outcomes. Results A retrospective cohort study was performed on 616 patients who underwent frozen embryo transfer (FET) cycles at a single reproductive center from January 2021 to December 2023. The participants were categorized into two groups based on the cryoprotectant used for blastocyst vitrification: sucrose or trehalose. Key outcomes, including implantation rates, proportions of good-quality and poor-quality blastocysts, and clinical pregnancy outcomes, were compared between the groups. A comparative analysis of the sucrose-based and trehalose-based groups yielded the following outcomes: The implantation rates were significantly higher in the trehalose-based group compared to the sucrose-based group (52.84% vs. 43.94%, p < 0.05). The proportion of good-quality blastocysts was significantly higher in the trehalose-based group (63.68% vs. 55.41%, p < 0.01). The proportion of poor-quality blastocysts was significantly lower in the trehalose-based group (2.20% vs. 8.08%, p < 0.001). Conclusions Trehalose-based vitrification solution was associated with improved implantation rates and better post-warming blastocyst quality compared to sucrose-based one. However, since the trehalose-based solution was commercially available, while the sucrose-based solution was laboratory-prepared, the observed differences may not solely be attributed to the type of sugar used. Future studies should aim to clarify the independent effects of trehalose by comparing it with sucrose under standardized conditions within the same type of vitrification solution.