Simple lateral ventricular widening at 31 weeks of pregnancy needs to be rechecked on time under the guidance of a doctor. The normal width of fetal lateral ventricle during pregnancy is <1.0cm, when ultrasonography suggests that fetal lateral ventricle is 1.0-1.5cm, it suggests ventricular widening, when ≥1.5cm, it suggests hydrocephalus, when ultrasonography suggests simple lateral ventricular widening in 31 weeks of pregnancy, and MRI does not combine with other structural abnormality, it can be dynamically observed under the instruction of the doctor, and rechecked on time. When fetal lateral ventricle widening is detected by ultrasonography during pregnancy, MRI and eugenic tests should be performed as prescribed by the doctor to exclude the risk of other structural abnormalities. In the case of simple lateral ventricular widening during pregnancy, the newborn should be rechecked in the postpartum period, and physical and mental development should be measured on time under the guidance of the pediatrician, as well as early developmental abnormalities, and intervention should be given in due course. Pregnant women should undergo proper obstetric examination according to the doctor's instruction. If fetal malformation is found, it is recommended to go to the regular hospital as soon as possible to do eugenics counseling and follow the doctor's instructions for treatment.