The aim of the current study was to establish a method of preclinical screening for ROP, in patients of less than 32 weeks gestational age and/or birthweight of less than 1500 g, based on the following criteria: serum IGF1 levels and/or presence of clinical, analytical or microbiological sepsis in the 3rd week post-partum, gestational age and birthweight. This evidence concerns the gene IGF1 and Sepsis.