A large abdominal circumference does not necessarily mean that the fetus is fat, but may also be related to more amniotic fluid, fetal chromosomal abnormalities, and so on. During pregnancy, the abdominal circumference of pregnant women may increase with the increase of pregnancy weeks, which is mainly related to the gradual development of the fetus and the increase of amniotic fluid. Usually, large abdominal circumference is related to fetal fatness, but it may also be related to high amniotic fluid volume in the uterus, over-nutrition of the body due to lack of attention to dietary care during pregnancy or increase in abdominal fat, twin pregnancy, diabetes mellitus, etc., which should be identified. If the examination reveals a large abdominal circumference of the fetus, it may also be related to fetal fatness, but it should also be alerted to other factors such as chromosomal abnormalities and malformations of the fetus. For those with abnormal abdominal circumference test results, it is necessary to further combine with other tests to determine the cause of the disease and whether the development of the fetus is abnormal. It is recommended to pay attention to the reasonableness of the diet during pregnancy to ensure a balanced intake of nutrients and avoid overeating. If the abdominal circumference of the fetus is enlarged, it is recommended to increase the number of checkups in order to monitor the development of the fetus and deal with the abnormalities in a timely manner.