Evidence exists for both genetic and environmental components and a multifactorial interaction appears likely. Prevention of recurrence of a NTD is reduced 5-10 fold by a woman's taking a high dose of folic acid starting one month prior to conception and continuing for the first 3 months of pregnancy. A similar prophylactic effect on first occurrences in a family is also likely using only moderate dietary supplementation. Small, low-lying defects may allow normal development with little physical handicap. Seventy percent develop hydrocephalus with a requirement for multiple neurosurgical procedures.
Mental retardation is exacerbated by infections.