Retinopathy of prematurity and serum level of insulin-like growth factor-1

The aim of our study was to measure and compare serum insulin-like growth factor-1 (IGF-1) levels at postmenstrual age of 33 weeks between preterm infants with and without retinopathy of prematurity (ROP). ROP occurs in two phases. Low serum levels of IGF-1 during ROP phase 1 have been found to correlate with the severity of ROP. ROP phase 2 begins around postmenstrual week 33. We conducted a prospective cohort study to measure serum IGF-1 levels in premature infants at postmenstrual age of 33 weeks. The study included all premature infants (N = 74), gestational age < or = 33 weeks, hospitalized at Department of Neonatology, Clinical Center of Montenegro, from April 2008 to July 2009. The incidence of ROP in the study cohort was 50.7%. Infants with ROP had a significantly lower birth weight and significantly shorter gestational age. The mean level of IGF-1 at postmenstrual age of 33 weeks was 23.7 mcg/L. Study results showed that there was no significant difference in serum IGF-1 level between newborns with and without ROP at postmenstrual age of 33 weeks (in newborns with ROP, it was the beginning of ROP phase 2). A large controlled study with repeated measurement of IGF-1 level in the neonatal period is needed to confirm that restoration of IGF-I level occurs in ROP phase 2, i.e. that the low level of IGF-1 is only a feature of ROP phase 1.