During the rapid growth period of the fetus, the fetal brain sometimes develops faster than the aqueduct system in the brain, and mild hydrocephalus occurs when the amount of hydrocephalus produced in the brain is significantly greater than the capacity of the aqueduct system to circulate. However, this slight hydrocephalus will gradually disappear as the aqueduct system in the brain develops. Absorption of lateral ventricular widening is related to the severity of the widening and the week of gestation. In mild cases, absorption is usually fastest at 26-32 weeks; in severely widened, hydrocephalic fetuses, retention is not recommended. Lateral ventricular widening is caused by impaired cerebrospinal fluid circulation and is usually classified as mild or severe. Mild refers to fetuses with an internal diameter of the lateral ventricle of 1-1.5 cm, while severe refers to fetuses with an internal diameter of the lateral ventricle greater than 1.5 cm. Lateral ventricular widening increases in absorption beyond 26-32 weeks, and the degree of widening decreases, but is rarely completely absorbed, so pregnant women should have prenatal diagnosis of lateral ventricular widening. In addition, fetuses with mild to moderate lateral ventricular widening rarely require surgical intervention after birth, while fetuses with severe lateral ventricular widening should undergo prompt surgical intervention after birth. Therefore, it is important to screen for fetal malformations during pregnancy and to perform ultrasonography once every 2-4 weeks in children with simple ventricular widening and to monitor ventricular dilatation dynamically.