This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pediatrics
[{'content': 'Most common cause of fetal ventriculomegaly is? \nSelect and explain. \nA. Arnold Chiari malformation -I, B. Arnold Chiari malformation -II, C. Aqueductal stenosis, D. Dandy Walker malformation', 'role': 'user'}, {'content': "Answer: C \nExplanation: Ans. is 'c' i.e., Aqueductal stenosis Hydrocephalus is characterized by an increased CSF volume with progressive ventricular dilatation (ventriculomegaly). o Obstructive or noncommunicating hydrocephalus/ventriculomegaly develops most commonly in children because of an abnormality of the aqueduct or a lesion in the 4' ventricle. o Obstruction of the aqueduct is the single most common cause of fetal and neonatal hydrocephalus/ ventriculomegaly. o Nonobstructive or communicating hydrocephalus most commonly follows a subarachnoid hemorrhage, which is usually a result of intraventricular hemorrhage in a premature infant.", 'role': 'assistant'}]