Although ART has markedly advanced, the likelihood of achieving pregnancy from transferred human embryos remains limited. Presently, embryo evaluation relies largely on morphological characteristics, which provide weak predictive information, as only a small portion of top-graded embryos result in successful pregnancy. Research has suggested that analyzing metabolites in embryo culture media could improve embryo selection. In this investigation, 66 human embryo culture media samples were analyzed in a blinded manner, five days after in vitro fertilization, to measure compounds produced by cellular metabolism that are not normally found in culture media, including purines, pyrimidines, nitrite, and nitrate. Among purines, only hypoxanthine and uric acid were detectable in most samples, while nitrite and nitrate were consistently present. When biochemical findings were compared to morphological grades, lower-quality embryos (n = 12) showed significantly elevated levels of all measured metabolites. Further comparison based on pregnancy outcome revealed that embryos from unsuccessful pregnancies (n = 25) released higher concentrations of hypoxanthine, uric acid, nitrite, and nitrate than embryos resulting in successful pregnancies (n = 17). All embryos leading to successful pregnancies produced healthy newborns. Although performed on a limited sample set, these results suggest that metabolite analysis in embryo culture media could serve as a valuable tool for selecting embryos, potentially improving ART success rates.
