We conducted random effects meta-analyses for % of 24-h time in range of 63–140 mg/dL (TIR), time in hyperglycaemia (> 140 mg/dl and > 180 mg/dL), hypoglycaemia (< 63 mg/dl and < 54 mg/dL), total insulin dose (units/kg/day), glycemic variability (%), changes in HbA1c (%), maternal and fetal outcomes. The gene discussed is INS; the disease is Hyperglycemia.