Higher odds of ROP in neonates born with lower Hb <12 gm/dL (OR 3.2), 12-14 gm/dL (OR 4.9), and 14-16 gm/dL (OR 1.9) compared to those neonates born with Hb >18 gm/dL were found in the above study [14]. This evidence concerns the gene GSTM1 and retinopathy of prematurity.