The Medical Task Force on anencephaly coordinated by Stumpf DA (Northwestern University Medical School, Chicago) presents a consensus statement limited to medical issues of organizations of physicians caring for fetuses and infants with anencephaly. The statement was approved by the AAP, AAN, ACOG, ANA, and CNS. Anencephaly is defined as a congenital absence of a major portion of the brain, skull, and scalp with its genesis in the first month of gestation. The primary abnormality is failure of cranial neurulation, the embryologic process that separates the precursors of the forebrain from amniotic fluid. Anencephaly does not mean the complete absence of the head or brain. Craniofacial anomalies are associated and up to 1/3 have defects of the non-neural organs that could preclude their use for transplantation. The maternal serum a-fetoprotein level is elevated in 90% of cases, and elevated a-fetoprotein levels in amniotic fluid and the presence of acetylcholinesterase on electrophoresis occur in virtually all cases. Ultrasonography is also reliable in the prenatal diagnosis of anencephaly. The postnatal diagnosis requires the following criteria: 1) Absence of a large portion of the skull, 2) absence of scalp over skull defect, 3) exposed hemorrhagic fibrotic tissue, 4) absence of recognizable cerebral hemispheres. The cause is usually not known and a polygenic or multifactorial etiology is suggested. Chromosome abnormalities and mechanical factors are recognized associations. Hyperthermia and deficiencies of folate, zinc and copper in the mother have been invoked. In recent years, 80-90% are aborted, 7-10% are stillborn, and 3-11% are live born. Most live born anencephalic infants have died within the first days after birth and survival beyond one week occurred in 0-9% in three series. Two months was the longest survival confirmed with accepted diagnostic criteria. The estimated incidence of anencephaly in the U.S. is 0.3-7/1000 births and the incidence of live born infants with anencephaly would be less than 100 per year. Anencephalic infants have no functioning cerebral cortex and are permanently unconscious. Brain stem functions are present in varying degrees and the diagnosis of brain stem death depends on the disappearance of previously existing brain stem functions, including loss over an observation period of at least 48 hours of measurable cranial nerve function and spontaneous movements, and a positive apnea test. Confounding factors such as drugs, hypothermia, or hypotension should be excluded. The use of organs from infants with anencephaly for transplantation is also discussed. [1]