Preterm pigs born at 90% of full gestation exhibit highly immature gut functions, with the highest NEC-sensitivity and mortality in the first 1–2 weeks of life,43,62 while extremely preterm infants remain sensitive for a longer period.63 Differences in interspecies organ development trajectories warrant careful consideration when applying results of experimental IGF-1 therapy studies to humans, particularly given its multi-organ effects. Here, IGF1 is linked to necrotizing enterocolitis.