Elevated blood glucose at 2-8 weeks of gestation can lead to a significant increase in fetal malformations, and maternal hyperglycemia in mid- to late pregnancy can also increase fetal complications, such as intrauterine growth retardation, macrosomia, neonatal hypoglycemia, respiratory distress syndrome and hyperbilirubinemia. In pregnant women, hyperglycemia also increases the risk of hyperemesis, hyperhydramnios, birth injury due to macrosomia, postpartum hemorrhage, and puerperal infection. Therefore, it is important for women with diabetes to plan their pregnancy so that conception is safer for both mother and baby if their preprandial glucose is 4.4-6.1 mmol/L, 2h postprandial glucose is <8.6 mmol/L, and HbA1c is <7.0%. For pregnant women, even if they have no previous history of diabetes, their blood glucose will drop after pregnancy in order to supply the fetus with sufficient energy. Keeping the blood glucose stable and up to standard throughout pregnancy can reduce the occurrence of the above complications. Therefore, in order to ensure a good pregnancy outcome and protect the health of both mother and baby, the goal of blood glucose control for pregnant women should be more strict. Pregnant women's blood glucose will fluctuate due to the influence of glucose-raising hormone secreted by the placenta, therefore, some patients need to monitor their blood glucose eight times a day, including three meals before, three meals 1h after, bedtime and midnight blood glucose. If a pregnant woman's blood glucose monitoring value exceeds 8.9 mmol/L, an additional dose of insulin needs to be injected (not pumped) immediately to avoid diabetic ketoacidosis. It is well known that childbirth is one of the four major stresses in the human body, during which maternal blood glucose should be controlled at 3.5-5.6 mmol/L to ensure a smooth labor. Maternal blood glucose >6.7mmol/L will stimulate the increase of fetal insulin secretion and lead to the occurrence of neonatal hypoglycemia. Therefore, it is necessary to monitor maternal blood glucose every hour after delivery and adjust the basal insulin dose in time to stabilize the blood glucose level during the whole labor.