Some studies have shown that miRNAs expression is linked to GDM occurrence, and aberrant expression of miRNAs in human placenta leads to the pathogenesis of GDM, such as miR-296, an expression of which is improperly down-regulated in placenta with GDM in clinic and affects human placental development through the alterations in migration and invasion of trophoblast cells by regulating HIF3A [15]. The gene discussed is HIF3A; the disease is gestational diabetes.