It is normal that the difference between the far field and the near field of the lateral ventricle is within 10 mm. According to relevant published data, the lateral ventricle width reported by ultrasound is less than 10mm, whether it is 8mm or 6mm, which means that the lateral ventricle width of the baby is normal. The lateral ventricle width greater than 10mm is called lateral ventricle widening. Widening of lateral ventricle is an ultrasonic sign of fetal lateral ventricle body width measured by ultrasound in the second and third trimester of pregnancy.