Metabolite Profiling in Maternal Serum

Conventional clinical metabolite and targeted metabolomics assays were conducted as previously described using maternal serum obtained fasting and 1 h after a glucose load [17 (link),18 (link)]. Briefly, 15 amino acids, 45 acylcarnitines and 5 conventional clinical and targeted metabolites were analyzed. Levels of conventional clinical metabolites, including lactate, triglycerides, 3-hydroxybutyrate, glycerol, and nonesterified fatty acids (NEFA), were measured on a Unicel DxC 600 clinical analyzer (Beckman Coulter, Brea, CA, USA). Targeted metabolomics assays for acylcarnitines and amino acids were conducted by tandem mass spectrometry (MS) with addition of known quantities of stable isotope-labeled internal standards on an Acquity TQD Triple Quadrupole system (Waters Corporation, Milford, MA, USA).