Adverse factors in the family and maternal history, pregnancy, and birth related to the occurrence of neonatal encephalopathy (NE) in full term newborn infants were evaluated in a matched case-control study at the Institute for Child Health Research, West Perth, and the Department of Neonatology, Princess Margaret Hospital for Children, Subiacco, Western Australia. Of 89 cases studied, 42 met criteria for moderate or severe neonatal encephalopathy: severe NE -mechanical ventilation required for >24 hours, multiple anticonvulsants, coma, or death; moderate NE: -neurologic abnormalities or seizures requiring anticonvulsants, but resolving before discharge. The estimated incidence of NE in the first week of life was 3.75 per 1000 full term live births, and a case fatality of 8%. Intrapartum hypoxia was the cause of NE in only 5 cases, and antepartum factors were more significant and frequent. Maternal vaginal bleeding in pregnancy, physical trauma during pregnancy, maternal thyroxine treatment, and congenital abnormalities were significantly more frequent in NE patients than in controls. Maternal alcohol consumption, smoking during pregnancy, and gestational diabetes were not related to NE. 
COMMENT. Antepartum factors and preexisting neurologic abnormalities are important in the cause of neonatal encephalopathy occurring in full term infants. Intrapartum hypoxia is significant in only 6% of cases.
Problems with definitions and classifications of newborn encephalopathy are reviewed in Progress in Pediatric Neurology II, 1994, pp321-2. The clinical features of hypoxic-ischemic encephalopathy are not specific, and similar symptoms may be caused by metabolic disorders, infection or cerebral malformations.