Perinatal differences in asphyxic full-term newborns in relation to the presence of hypoxic-ischemic encephalopathy

Objective: To study the perinatal differences of full-term newborn infants with perinatal asphyxia in relation to their neurologic manifestations (postasphyctic encephalopathy).

Methods: Prospective epidemiologic study over perinatal asphyxia in full-term infants born in our hospital between november 1991-february 1995. Perinatal asphyxia was graded as non-severe (first minute Apgar score < or = 6 and/or umbilical artery pH < 7.20, with abnormal fetal heart rate patterns and/or meconium stained amniotic fluid, and the need for immediate neonatal resuscitation) and severe (first 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. The perinatal variables were graded as prenatal (gestationals and obstetrics), neonatal (resuscitation, general data of the newborn, and organic manifestations of asphyxia) and postneonatal (neurologic sequelae at follow-up).

Results: During the study period there were 3,342 full-term, live births. Perinatal asphyxia developed in 156 (31 severe and 125 non-severe). Neurologic manifestations were present in 25.6% of asphyxiated newborns: 40 cases of hypoxic-ischemic encephalopathy (mild in 30, moderate in 5 and severe in 5). The main differences between asphyxiated newborns with and without hypoxic-ischemic encephalopathy were: chronic maternal diseases, pathologic obstetric antecedents, distocic deliveries, neonatal resuscitation, severity of perinatal asphyxia, sex and weight of newborns, days and origin of admission, birth injury, extraneurologic manifestations (mainly pulmonary, digestive, haemodynamic and cardiologic) during neonatal period, and neurologic sequelae at follow-up.

Conclusions: The main perinatal differences in relation to postasphyctic encephalopathy are important in the knowledgement of their pathogenic mechanism (interrelation between neurologic and extraneurologic manifestations) and their follow-up (hypoxic-ischemic encephalopathy is the most important prognostic factor of neurologic sequelae in the full-term asphyctic newborn).