Our previous studies found that sows’ obesity during pregnancy significantly inhibited the expression of vascular endothelial growth factor (VEGF), and decreased the placental vascular density, resulting in reduced placental vascular, resulting in reduced placental vascular development, poor placental function and compromised fetal growth and development, thus increasing the generation of weak offspring with body weight ≤0.9 kg [9]. The gene discussed is VEGFA; the disease is obesity due to melanocortin 4 receptor deficiency.