Evidence of Intrapartum Hypoxia-Ischemia Is Not Present in the Majority of Cases of Neonatal Seizures

Abstract

Although external fetal monitoring reportedly has had the effect of reducing neonatal seizures, the incidence of cerebral palsy has changed little over the past four decades. Seizures are the commonest indication of neurologic disorder in the first month of life. This case-control study was an attempt to quantify the association between neonatal seizures and intrapartum hypoxia-ischemia as manifested by metabolic acidosis. Newborn infants seen at a single center with seizures were matched in a 2:1 ratio with control infants of similar gestational age who had no seizures. Over the 11 years of the study, 1988 to 1999, 13 neonates had seizures; 1 of these neonates was excluded because of a chromosomal abnormality. The 12 case infants had a mean gestational age of 35 weeks at the time of delivery. Four deliveries were preterm, as were 8 of 24 deliveries of control infants. The two groups did not differ significantly in maternal age, parity, or race. Seizures significantly extended the hospital stay. A 5-minute Apgar score less than 7 was twice as frequent in case infants (33% vs. 17%), but the difference was not statistically significant. The mean base excess in arterial cord blood was -7.6 mEq/liter in case infants and -2.8 mEq/liter in control infants. The mean umbilical arterial pH was 7.17 for case infants and 7.28 for control infants. Only 3 of 10 the case infants evaluated (and none of the control infants) had a pH less than 7.00. One of these 3 infants was a preterm birth. These findings do not support the supposition that most newborn infants with seizures also have intrapartum hypoxia-ischemia. More than two thirds of the present neonates with seizures lacked evidence of metabolic acidosis at the time they were born.