Risk factors

In many cases, the cause of hydrocephalus is unknown. However, a number of developmental or medical problems can contribute to or trigger hydrocephalus.

Newborns

Hydrocephalus present at birth (congenital) or shortly after birth can occur because of any of the following:

• Abnormal development of the central nervous system that can obstruct the flow of cerebrospinal fluid
• Bleeding within the ventricles, a possible complication of premature birth
• Infection in the uterus — such as rubella or syphilis — during pregnancy, which can cause inflammation in fetal brain tissues

Other contributing factors

Other factors that can contribute to hydrocephalus among any age group include:

• Lesions or tumors of the brain or spinal cord
• Central nervous system infections, such as bacterial meningitis or mumps
• Bleeding in the brain from a stroke or head injury
• Other traumatic injury to the brain