Urinary metabolomics in term newborns delivered spontaneously or with cesarean section: preliminary data

Introduction: In the last years the uncritical attitude towards cesarean section (CS) has been associated with the fast emergence of ‘modern' diseases such as early pediatric obesity, asthma, type 2 diabetes mellitus and dermatitis. Increasing evidence shows that babies born at term by vaginal delivery (VD) have a different physiology at birth, with subsequent influence on adult health. In relation to these short-term physiological changes, in the present study we aimed at assessing the influence of the mode of delivery in term newborns on the first 24 hours metabolism of neonates. Material and methods: This study was carried out on urine samples from 42 patients admitted to the Neonatal Intensive Unit and Neonatal Pathology of “S. Giovanni Calibita” Hospital Fatebenefratelli (Rome, Italy). According to the type of delivery, term neonates with similar gestational age and birthweight were divided in two groups: (1) born by spontaneous VD, (2) born by elective CS. Urine samples, collected at birth by a non-invasive method, were subjected to proton Nuclear Magnetic Resonance spectroscopy. Results: CS newborns showed lower fatty acid omega oxidation, as evidenced by lower urinary excretion of dicarboxylic acids. This metabolic signature supports current evidence that babies delivered by CS have lower body temperature and perturbed thermogenesis. CS associates also with hypoglycaemia and altered endocrine profile, which linked to changes in central energy metabolic pathways (Krebs and Cori Cycles). Lung function may be reduced in infants born by CS, primarily due to delayed clearance of lung liquid, and surfactant insufficiency, which might be reflected in different urinary excretion of myo-inositol and choline - two intermediates in lung surfactant metabolism. Conclusion: Non-invasive urine metabolic phenotyping of children born by different mode of delivery provides relevant readouts to assess metabolic requirements associated with major physiological functions during this critical period of metabolic adaptation.