Study outcomes
heartbeat and breath
The primary goal of a scheduled PGT-A cycle is to obtain euploid blastocysts for transfer. Therefore, the primary outcome was the proportion of cycles which obtained euploid blastocysts, calculated as the number of cycles with ≥ 1 euploid blastocyst divided by the total number of OS cycles in a cohort. Secondary outcomes included euploid blastocyst rate per cohort (total number of euploid blastocysts in a cohort/total number of biopsied embryos in the same cohort) and euploid blastocyst rate per cycle (number of euploid blastocysts obtained in a cycle/number of blastocysts obtained in the same OS cycle). The mean euploid blastocysts per cycle were calculated separately considering the OS cycle and biopsy cycle. A biopsy cycle was defined as the OS cycle with blastocysts for biopsy and genetic testing. If no blastocysts or euploid blastocysts were obtained after OS, the euploidy rate of this cycle was zero. Additional outcomes of interest included embryo implantation, clinical pregnancy, and ongoing pregnancy. Embryo implantation was defined as positive serum β-HCG levels 14 days after embryo transfer. Clinical pregnancy was defined as the visualization of the gestational sac on ultrasonography. Ongoing pregnancy was confirmed if a pulsating fetal pole was present at 12 weeks of gestation. Live birth was deliveries ≥ 22 weeks gestation with heartbeat and breath. All transfer outcomes were followed up until June 2023.