Compared with full-term infants, neonates born very preterm (<32 weeks of gestation) have a sustained period of low-plasma IGF-1 levels (Lineham et al., 1986; Hellström et al., 2016), and a decrease in levels correlates with several morbidities, such as postnatal growth restriction (Kajantie et al., 2002), retinopathy of prematurity (ROP; Liegl et al., 2016), bronchopulmonary dysplasia (Hellström et al., 2003; Löfqvist et al., 2012), and necrotizing enterocolitis (NEC; Hansen-Pupp et al., 2011, 2013; Beardsall et al., 2014; Hellström et al., 2016). Here, IGF1 is linked to retinopathy of prematurity.