This retrospective data analysis demonstrated inadequate provision of parenteral nutrition in our NICU, which was often not in line with current German guidelines. This was associated with inadequate growth in our cohort, most notably during the first 3 weeks of life; however, implementation of current guidelines is impeded by metabolic disturbances in this cohort, most notably in ELBW neonates. Whether adherence to published guidelines will result in better early ex utero growth, and whether this normalized growth pattern will translate into better long-term outcome on a metabolic and neurological level, remains unclear.