The size of the fetus is estimated by the uterine height and abdominal circumference during pregnancy. The normal uterine height of a pregnant woman at 30 weeks is between 24 and 30.5 cm, and the abdominal circumference generally grows at about 20 cm throughout pregnancy. Some statistics show that the abdominal circumference is around 94-107cm throughout pregnancy, with an average of around 97cm. Due to large individual differences, abdominal circumference is no longer used as the main indicator to assess the size of the fetus. If the abdominal circumference grows too fast, it may be caused by the overgrowth of the fetus, amniotic fluid, etc. It is recommended to check the height and weight of the fetus by ultrasound. If the fetus is large, you need to pay attention to control the diet, usually do not eat too much fatty food, if the amniotic fluid is large, no symptoms, you can observe, regular monitoring, and pay attention to check whether there are fetal malformations, too much amniotic fluid, the fetus is prone to gastrointestinal and urinary system malformations. If the abdominal circumference is small, it may be caused by factors such as thinness of the pregnant woman, malabsorption of the fetus, and the position of the fetus in the uterus. It is recommended to assess whether the fetus is developing normally, and if necessary, to increase the nutrition of the pregnant woman appropriately to ensure a balanced intake of fat, protein, vitamins and various trace elements, etc. The growth of abdominal circumference alone is a limited and one-sided measure of uterine and fetal growth.