Baby head small abdomen large may be due to abnormal blood sugar during pregnancy, at this time pregnant women need to carry out blood sugar monitoring, control blood sugar, but there may also be genetic factors, fetal development abnormalities, at this time can not be controlled. 1. Abnormal blood sugar during pregnancy: first of all, pregnant women can control the intake of sugar, reduce the intake of fruits containing more sugar, can intake of high-quality protein, if necessary, can use insulin to control blood sugar. 2. Genetic factors: If both parents or one of them has a small head and a large abdomen, there may be a certain genetic predisposition, which will lead to the baby’s small head and large abdomen, so it is a normal phenomenon. 3. Abnormal fetal development: it may be caused by the malformation of the fetus itself, or hydrocele or foreign body in the abdominal cavity, which requires further examination and diagnosis. If the baby’s head is small and the abdomen is large, further examination should be carried out, and treatment should be carried out according to the cause.