[Neurological evolution of asphyctic full-term newborns with severe umbilical acidosis (pHUA <7.00)]

Umbilical arterial blood pH (pHUA) has become increasingly recognized as the most reliable indication of foetal oxygenation and acid-base condition at birth. In term infants pHUA is a poor predictor of newborn complications associated with perinatal asphyxia (PA), unless the pHUA is less than 7.00. The objective of this article is to analyse the neurologic evolution of asphyctic full-term newborns with severe umbilical acidosis (pHUA < or = 7.00).

One hundred and eighty consecutive asphyxiated term infants were studied during 64 months, and classified in two cohorts: G1 (pHUA < or = 7.00, n = 18) and G2 (pHUA > 7.00, n = 162). Variables prospectively obtained on standard protocol forms from the medical records were derived from a detailed review of the obstetric record, the delivery room management, the detailed neonatal clinical history and the postneonatal follow-up. The perinatal variables were graded as prenatal (gestational and obstetric), neonatal (resuscitation, general data of the newborn, and organic manifestations of asphyxia) and postneonatal (neurologic sequelae with at lest 24 months of follow-up). PA was graded as severe and non-severe, hypoxic-ischemic encephalopathy was based on Levene's criteria, and neurologic sequelae were based on Finer and Amiel-Tisson's criteria.

An umbilical artery pH value < or = 7.00 occurred in 0.3% of the total live full-term newborns. In G1 the mean pHUA value was 6.93 +/- 0.06 (range 6.80-7.00) and in G2 the mean pHUA value was 7.17 +/- 0.09 (range 7.01-7.46). The incidence of severe PA was significantly increased in G1 (RR = 4.74, CI 95% = 2.62-8.55, p < 0.001), with more postasphyctic neurologic (RR = 3.72, CI 95% = 2.34-5.92, p < 0.001) and extraneurologic (RR = 3.13, CI 95% = 1.65-5.94, p < 0.01) involvement. But we do not found differences in the incidence of neurologic sequelae between both cohorts.

Term asphyctic newborns with severe umbilical acidosis have worse evolution at short term (more clinical involvement during neonatal period), but not worse evolution at long term (neurologic sequelae). The poor correlation between umbilical acidosis and neurologic prognosis persist when pHUA cut-off is < or = 7.00.