How do other illnesses affect congenital hydrocephalus?

Experts think that problems with fetal development known as neural tube defects can contribute to congenital hydrocephalus. Neural tube defects are birth defects that involve the brain, the spinal cord, and the tissue that surrounds the spinal cord. Spina bifida (a malformed spinal cord) and encephalocele (protruding brain tissue) are examples of neural tube defects that could increase the risk of hydrocephalus. It has been estimated that 70 to 90 percent of children with spina bifida also have hydrocephalus.