Causes of neonatal hydrocephalus: 1. Neonatal hydrocephalus is caused by excessive cerebrospinal fluid production or impaired circulatory absorption: the cerebrospinal fluid stagnates in the ventricular system or subarachnoid space and grows, the pressure increases, and the ventricles expand, i.e., hydrocephalus is a congenital malformation: such as midbrain aqueduct stenosis, diaphragm formation or atresia, interventricular foramen atresia malformation (fourth ventricle median foramen or lateral hollow atresia), cerebrovascular malformation, spina bifida The fetus may have a fetus with a subungual herniation of the cerebellar tonsils, etc. 2, infection: intrauterine infections such as various viruses, protozoa and syphilis spirochete infectious meningitis are not controlled early enough, the proliferating fibrous tissue blocks the circulatory orifice of cerebrospinal fluid, or fetal intracranial inflammation can also occlude the cerebral pool, subarachnoid space and arachnoid granules adhesions. 3, hemorrhage: intracranial hemorrhage caused by fibrous hyperplasia, intracranial hemorrhage from birth injury malabsorption, etc. 4, tumor: can block any part of the cerebrospinal fluid circulation, more often seen near the fourth ventricle, or choroid plexus papilloma. Others: certain hereditary metabolic diseases, perinatal and neonatal asphyxia, severe vitamin A deficiency, etc.