The overall objective of our research is to prevent the blinding eye disease retinopathy of prematurity (ROP) in preterm infants. The proposed project aims to determine how the serum metabolome of extremely preterm infants (born before 28 weeks’ gestation) relates to ROP development and clinical actions. Our specific aims are: • Identify serum metabolites and/or metabolite patterns in the neonatal period that can predict the later onset of ROP and shed light on disease etiology • Determine direct and indirect effects of parenteral nutrition on the infant’s metabolome • Relate longitudinal metabolic patterns to protein expression and lipidomics data In the current project, we will perform an in-depth analysis of the preterm infant serum metabolome in serial samples collected from birth to term equivalent age (40 weeks postmenstrual age). The metabolomics study is performed in collaboration with Chalmers Mass Spectrometry Infrastructure and includes 1535 serum samples collected from 179 infants born <28 weeks’ GA, as part of the recent randomized multicenter clinical trial Mega Donna Mega.