Data regarding perinatal asphyxia rates from 2001 indicate a prevalence rate of 25 per 1000 term live births and 73 per 1000 preterm live births, with 15 and 50% moderate to severe cases, respectively. The overall incidence of NE attributable to perinatal asphyxia was ∼1.6 per 10,000 live births in the absence of preconception or antepartum abnormalities. European data indicate an overall CP rate of 2.08 per 1000 live births for the period 1980–1990, with increased rates seen in infants with birthweight <1500 g. While earlier studies showed a stable rate of CP between the 1950s and 1990s, more recent data indicate a decline in the prevalence of CP for preterm infants born after 1980, possibly reflecting improved perinatal care. Only 8–17% of CP in term infants is associated with adverse perinatal events suggestive of asphyxia; the cause of ≥90% of cases remains unknown.