[Neonatal hypoxic-ischemic encephalopathy: Incidence and prevalence in the first decade of the 21st century]

To examine the incidence and the prevalence of neonatal hypoxic-ischemic encephalopathy (HIE) in a tertiary Spanish center over a 9-year period, before the implementation of a hypothermia program.

All infants > or =34 weeks gestation, born between 2000 and 2008 with evidence of perinatal asphyxia and neonatal encephalopathy were identified. HIE was classified as mild, moderate or severe. Joinpoint regression model was used to identify changes in the trends of HIE incidences.

A total of 90,963 live infants were born in La Paz Hospital between 2000 and 2008, and 23.3% of them (21.228) were admitted to the Neonatal Unit. In addition, 200 infants were referred from other centers. A total of 110 infants had HIE, of which 90% were inborn. The overall incidence of HIE was 1.088 per 1,000 live births, and the incidence of clinically significant HIE (moderate and severe grades) was 0.49 per 1,000 live births. The incidence of HIE showed a linear downward trend throughout the study period (slope=-5.37; P<0.05). Fifty-two neonates had moderate or severe HIE, this represents a prevalence of 2.42 per 1,000 infants admitted to the Neonatal Unit and means that 5-6 infants a year would have been candidates for therapeutic hypothermia.

Neonatal HIE, and in particular significant HIE, is an infrequent condition. The low prevalence of HIE requires that these infants are referred to regional centers with sufficient experience in the use of therapeutic hypothermia, and in the management of all the medical problems associated with HIE.