Low levels of circulating IGF-1 have been associated with several complications of prematurity (5), including growth restriction (6–9), systemic inflammation [early- or late-onset sepsis, (10, 11)], lung complications [bronchopulmonary dysplasia, BPD, (12)], gut inflammation [necrotizing enterocolitis, NEC, (9)], eye problems [retinopathy of prematurity, ROP, (9, 13)] and brain damage [intraventricular hemorrhage, IVH, (14, 15)]. This evidence concerns the gene IGF1 and bronchopulmonary dysplasia.