Fasting blood glucose does not get lower and lower in late pregnancy; instead, gestational diabetes may develop. In early pregnancy, in order to meet the growth and development of the fetus, the plasma glucose level of pregnant women decreases with the progress of pregnancy, and fasting blood glucose decreases by about 10%. However, in the middle and late stages of pregnancy, the pregnant woman’s body antagonizes the increase of insulin-like substances, insulin sensitivity decreases, and more insulin is needed to maintain blood glucose. If insulin is not secreted enough, it will lead to increased blood sugar and the development of gestational diabetes. When gestational diabetes develops, it is important to treat it aggressively. Pre-meal and 2-hour post-meal blood glucose values should be controlled at ≤5.3mmol/L and 6.7mmol/L respectively. Diet + exercise therapy is recommended to adjust the dietary structure, eat less sugary foods, and perform moderate-intensity exercise 30 minutes after meals, which can lower blood glucose. Pregnant women with gestational diabetes who have poor glycemic control may choose insulin to lower their blood glucose. Most pregnant women with gestational diabetes return to normal blood glucose levels with the end of labor. The OGTT can be repeated 6 weeks after delivery to see how blood glucose has recovered.