The normal value of the internal diameter of the left lateral ventricle is below 1cm and the normal average width of the lateral ventricle is around 0.7cm. A width of the lateral ventricle greater than 1cm is an important value that can facilitate the examination of what diseases exist in the fetal brain and can also avoid the risk of congenital mental retardation and hydrocephalus in the fetus. A left lateral ventricular internal diameter greater than 1.5cm indicates a very serious situation that requires abortion treatment, timely hospital examination and timely treatment after the diagnosis of wide lateral ventricles to prevent more serious consequences and side effects from occurring. Many pregnant women find that the lateral ventricles of their fetuses are about 1cm wide during pregnancy tests, and they are born healthy and do not need to be treated with birth control. The fetal lateral ventricle is divided into the left lateral ventricle and the right lateral ventricle. The lateral ventricle cannot be 0, but must be within the normal range, as long as it is under 1cm it is acceptable.