Severe congenital malformation of the brain and skull, in which the fetus lacks most of the brain, especially the cerebral hemispheres, and the skull is not fully formed.
Anecephaly occurs in the early stages of embryonic development due to impaired neural tube closure. Risk factors include genetic disorders, maternal folic acid deficiency, and exposure to teratogenic factors. Prevention is associated with the intake of folic acid before and during pregnancy.