Clinically, it is usually considered that the width of fetal lateral ventricle not more than 10mm is normal, and 10-15mm belongs to the range of suspected hydrocephalus. If the width of fetal right lateral ventricle is examined to be about 10.2mm, which is slightly larger than the normal value, it is necessary to review the examination regularly, and if necessary, to do further examination to clarify the diagnosis. The causes of right ventricular width can be divided into two types, one is congenital, often refers to fetal chromosomal abnormalities, and the other is the pregnant woman infected with viruses during pregnancy, common cytomegalovirus infection, both of which lead to abnormalities in the brain, manifested by wide ventricles. If the right ventricle is about 10.2mm wide and not accompanied by other abnormalities, it is usually not a big problem and can continue to be observed, and if necessary, amniocentesis or cranial MRI can be performed to clarify the diagnosis. When the right ventricle is found to be wide, attention should be paid to the presence of other abnormalities, and actively cooperate with the doctor for examination or treatment to avoid delaying the time of treatment.