Metabolic Profilingof Amniotic Fluid by Proton Nuclear Magnetic Resonance Spectroscopy:Correlation with Fetal Maturation and Other Clinical Variables

70 specimens of human amniotic fluid, representing preg-nancies at different stages of maturation and with different fetomaternal complications. Spectra with good signal-to-noise characteristicswere obtained in 3.5 mm of acquisi-tion time, directlyon untreated fluid, with presaturationto suppress the intense water resonance. Metabolites that generally gave rise to well-resolved resonances included lactate, glucose, creatinine, choline derivatives, citrate, acetate, alanine, glycine, glutamate, succinate, and oth-ers. For three of these metabolites-creatinine, glucose, and lactate-the peak intensities correlated well with re-sultsof conventionalchemical analysis. The NMR spectra of third-trimester specimens were readily distinguishable from those of second-trimester specimens, and several peak intensitiescorrelated with fetal maturationduringth