Neonatal outcome of infants with 1-minute Apgar score < 7

Abstract

Background : Apgar score describes the condition of newborn infants immediately after birth. Although, a low score alone is not correlated with the infant’s future outcome, it may remain meaningful for prediction of the infant’s survival and complication, such as hypoxic-ischemic encephalopathy (HIE).

Objective : To compare the incidence of HIE and death between preterm (GA < 36 weeks) and term infants (GA > 37 weeks) who had 1-minute Apgar score < 7.

Method : Medical records of all infants with 1-minute Apgar score < 7 at King Chulalongkorn Memorial Hospital during 2003-2005 were reviewed. HIE was diagnosed in the infants who had clinical finding of conscious change and seizures during the first 24 hours of age with or without abnormal EEG or abnormal computerized brain scan. Death incidence included all deaths that occurred during hospitalization regardless of their postnatal age.

Result : There were 1,470 out of 25,909 infants (5.56%) who had 1-minute Apgar score < 7. The incidence was significantly higher in preterm group (19.33% vs. 4.31%), (OR = 5.33, 95%, Cl, 4.72, 6.0, p - value <0.0001). The incidence of neonatal death in the preterm group was also higher, (8.99 % vs. 1.38 %), (OR = 7.06, 95% Cl, 3.81, 13.08, p - value < 0.0001). The incidence of HIE was however lower in preterm infant than those of term group, especially among those infants with score < 3, (2.75% vs. 20.56 %), (OR = 0.13, 95%, Cl, 0.04, 0.43, p-value <0.0001). Term infants with score < 3 developed HIE more often than those with higher score (20.56 % vs. 1.87%), (OR = 13.55, 95%, CI6.93, 26.50, p<0.0001). This association was not different in the preterm group. However, the mortality rate of both the preterm and term with score < 3 were higher compared with those with score of 4 - 7.

Conclusion : Preterm infants were at higher risk to have low 1-minute Apgar score, but they were less likely to develop HIE than term infants. 1-minute Apgar score < 3 can be used for prediction of HIE and death in term infants.