Clinical studies of GDM pregnancies have revealed an increase in maternal IGF-1 levels and a decrease in cord blood, and a positive correlation between insulin and IGF-1 fetal concentrations and birth weight of a newborn (69), suggesting the implication of this hormone in fetal intrauterine growth, that could lead to the development of macrosomia (70–72). This evidence concerns the gene IGF1 and gestational diabetes.