The project proposed by the fellow Evelyn Jantscher-Krenn and the scientist in charge, Gernot Desoye, Medical University of Graz, Austria, aims at pinpointing the potential role of Human Milk Oligosaccharides (HMO) as biomarkers in metabolic diseases in pregnancy. HMO are immunomodulatory glycans in breast milk that are also present in the systemic circulation of pregnant women. New evidence detecting HMO in the umbilical cord blood (fetal circulation), raises the question whether prenatal HMO can influence pregnancy outcomes and developmental programming of the fetus. In breast milk, HMO concentration and composition are dependent on genetic, but potentially also environmental factors. We therefore hypothesize that prenatal HMO have an impact on the health of mother and fetus, and are correlated with life-style induced metabolic changes. To test the hypothesis, three project objectives are formulated: Objective 1 longitudinally determines maternal HMO concentration and composition in serum to describe variability and temporal changes during pregnancy. Objective 2 determines fetal HMO concentration and composition in arterial and venous cord blood, in comparison to maternal HMO, to gain insight about origin. Objective 3 investigates associations of prenatal HMO (maternal/fetal) with both, maternal factors (maternal body mass index and physical activity) and fetal outcomes (fetal growth and body composition). Biological specimens for HMO analysis and data for objective 3 will be available through an existing cohort study. For the implementation of this IIF, the fellow will transfer HMO analysis methods from the University of California, San Diego, USA, and combine this knowledge and technology with expertise in Perinatology at the Medical University of Graz. As such, the project will contribute to establishing the emerging field of HMO research in Europe and form the basis for the fellow’s career vision of pioneering the field of HMO in Perinatology.