IGF1 and gestational diabetes: Some studies reported that higher fetal weight or macrosomia were observed in GDM mice, studies using high-fat diets to construct obese GDM mice have found that altered glucose, amino acid, and fatty acid transport in the placenta stimulates the release of endogenous insulin-like growth factor-1 by the fetus, resulting in fetal overgrowth, which is an explanation to some extent for the development of macrosomia in overweight GDM patients (11, 43, 44).