['Copeptin, the c-terminal part of pro-Arginine vasopressin, has recently been introduced as a novel risk factor to develop facets of the metabolic syndrome. However, regulation of copeptin in pregnancy-associated metabolic disease, i.\u2009e., gestational diabetes mellitus (GDM), has not been fully understood, so far.', 'For this study, 74 GDM patients and 74 healthy, pregnant, age-, body mass index-, and gestational age-matched controls were recruited. Serum levels of copeptin were quantified by an illuminometric assay. Furthermore, copeptin concentrations were correlated to biochemical and anthropometric markers of obesity, glucose and lipid metabolism, renal function, and inflammation.', 'Median [interquartile range] serum copeptin levels were significantly lower in subjects with GDM (3.5 [2.0] pmol/l) as compared to controls (4.4 [3.2] pmol/l) (p<0.05). Furthermore, GDM remained an independent predictor of circulating copeptin in multivariate regression analysis (p<0.05). Moreover, copeptin was independently associated with gestational age at blood sampling (p<0.05).'] Are serum Levels of Copeptin Decreased in Gestational Diabetes Mellitus?