There are two cases of high blood sugar in pregnant women, one is high blood sugar before pregnancy, already diabetic, and the other is high blood sugar after pregnancy. There are generally several reasons for high blood sugar in pregnant women: a. Not paying attention to the diet. During pregnancy, some pregnant women will eat many foods that contain a lot of sugar and a lot of fat, and the intake of these foods will increase insulin secretion. However, if the pregnant woman has more demand for insulin while the pancreas cannot secrete so much insulin, the pregnant woman’s blood sugar will be high. Second, there is a family history of diabetes. These pregnant women may carry genes that make them more likely to get diabetes. They should pay more attention to their eating habits, as bad habits may trigger the onset of diabetes. Third, pregnant women who are overweight. Because insulin hypoglycemic activity is related to body weight, the insulin hypoglycemic activity of overweight pregnant women is lower. Therefore, these pregnant women need to control their weight in order to keep their blood sugar normal. Fourth, it is caused by the change of hormone level. This is also the main reason why pregnant women are prone to blood sugar abnormalities. The placenta of pregnant women will secrete some hormones that can counteract insulin production, resulting in a decrease in insulin sensitivity and an increase in insulin demand, which can easily cause high blood sugar during pregnancy for pregnant women with limited insulin secretion. If a pregnant woman has a high blood sugar level, she should control her blood sugar under the guidance of her doctor.