In a randomized placebo-controlled trial, 121 extremely premature infants were allocated to supplementation with recombinant human (rh)IGF-1 or placebo.20 While IGF-1 supplementation did not affect the primary outcome (retinopathy of prematurity), it was associated with a reduced incidence of bronchopulmonary dysplasia and intraventricular hemorrhage. This evidence concerns the gene IGF1 and bronchopulmonary dysplasia.