Fetal lateral ventricular separation of 8 mm is usually not dangerous. The value of lateral ventricular separation varies with gestational age, stage and fetus. 10 mm or less of cerebrospinal fluid can be absorbed by the fetus on its own, so if the lateral ventricular separation does not exceed 10 mm, parents need not worry too much and there is usually no significant effect. If the fetus has a lateral ventricular separation of 8mm, it usually needs to be rechecked again after 1 month. A 4D ultrasound should be performed around 6 months of pregnancy to check for enlargement of the lateral ventricular separation. If there is no enlargement, parents should not worry. If there is a gradual increase in lateral ventricular separation and an increase in hydrocephalus, further examination is needed as soon as possible to clarify whether the increase is due to hydrocephalus or developmental abnormalities, or other conditions. If the fetus has widened lateral ventricles with enlarged choroid, it is necessary to pay attention to the possibility of chromosomal abnormalities, and further examination of cord blood chromosomes is recommended to exclude chromosomal disorders. In case of hydrocephalus or developmental abnormalities, amniocentesis or MRI can be performed to observe whether other brain tissues are also abnormal.