LEP and gestational diabetes: Recent studies have shown that the high glucose environment in GDM mothers can stimulate the secretion of various cytokines (such as insulin-like growth factor (IGF)-1/2, leptin, adiponectin, etc.)from the placenta into the fetus via umbilical vein and, in combination with high glucose in utero, stimulate the synthesis of fat in the fetus, thus causing fetal overgrowth (25–28).