[Perinatal asphyxia, hypoxic-ischemic encephalopathy and neurological sequelae in full-term newborns: an epidemiological study (1)]

Abstract

Introduction: Perinatal asphyxia, and its neurologic manifestations (hypoxic-ischemic encephalopathy) is the most important cause of brain injury and neurologic sequelae in full-term infants.

Objective: The aim of this study was to know the incidence of perinatal asphyxia, hypoxic-ischemic encephalopathy and neurologic sequelae in our full-term infants.

Material and method: Prospective epidemiologic study of perinatal asphyxia in full-term infants born in Universitary Hospital San Juan (Alicante, Spain) between November 1991-February 1995. Perinatal asphxyia was graded as non severe (1-minute Apgar score < or = 6 and/or umbilical artery pH < 7.20, with abnormal fetal heart rate patterns and/or meconiumstained amniotic fluid, and the need for immediate neonatal resuscitation) and severe (1-minute Apgar score < or = 3 and umbilical artery pH < 7.10). Hypoxic-ischemic encephalopathy was graded as mild, moderate and severe based on classification of Levene and Sarnat & Sarnat. Neurologic sequelae in 12-24 months follow-up was graded as mild, moderate and severe based on classification of Finer and Amiel-Tison.

Results: During the study period there were 3.342 full-term, live births. Perinatal asphyxia developed in 156 (31 severe and 125 non-severe), with an incidence of 4.66 cases per 100 full-term newborns. Neurologic manifestations was present in 25.6% of 156 term infants with perinatal asphyxia: 40 cases of hypoxic-ischemic encephalopathy (mild in 30, moderate in 5 and severe in 5). The incidence of hypoxic-ischemic encephalopathy was 1.19 cases per 100 full-term infants. The asphyctic newborns were regularly assessed. Ten infants was lost to follow-up. The incidence of neurologic sequelae, in 115 asphyxiated full-term infants follow-up at least 12-24 months, was 16.5%.

Conclusions: Despite the widespread use of the term perinatal asphyxia, there is little uniformity on the clinical definition of asphyxia, which makes comparison of incidence, treatment and outcome very difficult. The main epidemiologic differences in the studies of perinatal asphyxia and hypoxic-ischemic encephalopathy are due to little agreement on their definition. A consensus is necessary.