From innovation to practice: evaluating the evidence for preimplantation genetic testing for aneuploidy.

Pre-implantation genetic testing for aneuploidy (PGT-A) has been adopted widely despite lacking a complete evidence base. This review maps the 30-year evolution of PGT-A, from single-cell fluorescence in situ hybridization at the cleavage stage to blastocyst trophectoderm biopsy with comprehensive chromosome sequencing. Each advancement is evaluated against a framework for responsible development requiring analytical validation, predictive-value studies, and randomized controlled trials (RCTs) before clinical use. Repeated deviations from this pathway are documented: early iterations were introduced without validation, and modern versions entered routine practice before robust trials were completed. This premature adoption led to the discarding of potentially viable embryos. Critical appraisal of 6 contemporary RCTs reveals methodological shortcomings in the evidence base for PGT-A. These shortcomings include under-powered designs, enrolment of only good-prognosis patients, absence of cumulative live-birth outcomes, and exclusion of low- and medium-grade mosaic embryo transfers. Consequently, the current evidence does not justify the widespread use of PGT-A we see today.