Stefano Canosa, Christian Simon Ottolini, Antonio Capalbo, Giovanni Coticchio, Danilo Cimadomo, Alberto Revelli, Gianluca Gennarelli, Francesca Bongioanni, Laura Rienzi
Oocyte vitrification does not substantially alter the patterns of whole-chromosome aneuploidy in blastocysts from women of advanced maternal age. However, vitrification reduces oocyte resilience, mainly affecting developmental competence. Integrating chromosome-specific analyses, a refined framework was provided for interpreting PGT-A outcomes and personalizing IVF treatments in advanced maternal age patients.
RESEARCH QUESTION: Does oocyte vitrification affect chromosome-specific and age-dependent aneuploidy patterns in blastocysts from women of advanced maternal age?
DESIGN: This observational study included 163 aneuploid blastocysts derived from 441 fresh and 343 vitrified-warmed oocytes obtained from 122 patients of advanced maternal age undergoing oocyte accumulation for preimplantation genetic testing for aneuploidies (PGT-A). The blastocysts were compared based on whether they were derived from fresh or vitrified-warmed oocytes, obtained from the same patients. Chromosome-specific aneuploidy distributions were compared and age-related patterns were assessed by heatmap visualization and forest plot analyses. Age-dependent euploidy trends were evaluated by regression analysis. The number of euploid blastocysts obtained per inseminated metaphase II (MII) oocyte was calculated as an indicator of oocyte resilience to vitrification.
RESULTS: Euploidy rates declined with increasing maternal age in both cohorts, with comparable regression slopes between fresh and vitrified-warmed oocytes. Oocyte vitrification did not alter the global or chromosome-specific distribution of aneuploidies or their age-related dynamics. Chromosomes classically associated with age-dependent errors (16, 22, 21, 15, 18 and 13) showed similar age-dependent profiles in both cohorts. Despite preserved chromosomal stability, vitrified-warmed oocytes exhibited a significantly lower euploid blastocyst rate per inseminated MII oocyte, indicating reduced developmental competence.
CONCLUSIONS: Oocyte vitrification does not substantially alter the patterns of whole-chromosome aneuploidy in blastocysts from women of advanced maternal age. However, vitrification reduces oocyte resilience, mainly affecting developmental competence. Integrating chromosome-specific analyses, a refined framework was provided for interpreting PGT-A outcomes and personalizing IVF treatments in advanced maternal age patients.