Gestational diabetes mellitus blood glucose criteria are fasting blood glucose greater than 5.6 mmol/L, blood glucose greater than 10 mmol/L at one hour after a meal, and blood glucose greater than 8.5 mmol/L at two hours after a meal. Gestational diabetes mellitus is diagnosed by a 75 gram oral glucose tolerance test (OGTT) with fasting blood glucose greater than 5.1 mmol/L, one hour greater than 10 mmol/L, and two hours greater than 8.5 mmol/L. Gestational diabetes mellitus can be diagnosed by fulfilling one of the above three conditions. Gestational diabetes can have adverse effects on the fetus and the mother. More than half of pregnant women with gestational diabetes will develop type 2 diabetes within 10 to 20 years. Meanwhile, their fetus can be combined with miscarriage, infection, increased amniotic fluid, and may develop complications such as fetal respiratory distress syndrome, neonatal hypoglycemia, and neonatal erythrocytosis. It is recommended to seek medical attention and cooperate with doctors to start treatment once gestational diabetes mellitus is detected.