Mmu_circ_0002819 in mice aggravated dysregulated glucose metabolism (49.88 vs. 21.69 pM/mg, P=0.0031) and insulin sensitivity (0.20 vs. 0.11 mg/mL, P=0.03) in GDM mice, which was abrogated by the knockdown of mmu_circ_0002819. The gene discussed is INS; the disease is gestational diabetes.