Schwartz et al. reported that the increase in the concentration of IGF-1 in the umbilical cord blood is responsible for accelerating the intrauterine growth of the fetus, and the decrease in the serum concentration of IGFBP-1 in patients with GDM increases the bioavailability of IGF-1, which leads to the development of macrosomia [17]. The gene discussed is IGFBP1; the disease is gestational diabetes.