The effects of high blood glucose in pregnant women on the fetus include leading to giant fetus, intrauterine growth restriction, preterm labor, fetal malformation, and so on. 1. Huge fetus: maternal glucose can be transferred to fetus through placenta, when pregnant women with high blood glucose, the transferred glucose increases, and the fetus is in hyperglycemia, which stimulates the pancreatic islets to produce a large amount of insulin, which promotes the synthesis of fats, proteins, etc., and makes the fetus huge. 2. Fetal intrauterine growth restriction: it occurs in severe diabetic patients with vascular lesions, such as renal and retinal vascular lesions. 3. Preterm labor: Hyperglycemia can cause gestational hypertension, fetal distress, excessive amniotic fluid and other serious complications, which can lead to preterm labor. 4. Fetal malformation: the main reason is that metabolic disorders of pregnant women, especially hyperglycemia, are related to fetal malformation. Other factors are ketosis, hypoglycemia, hypoxia and diabetes treatment drugs. Pregnant women with high blood sugar should go to the hospital in time, under the guidance of the doctor standardized treatment.