Objective: To evaluate maternal and neonatal factors that predict low Apgar scores in newborns weighing less than 1000 g.
Methods: From a data set of all live-born infants who were delivered between 1979-1991 and who weighed 1000 g or less, we reviewed the records of 837 neonates born at 24-28 weeks' gestation. Potential risk factors were evaluated for associations with a 1-minute Apgar score of 3 or less and a 5-minute Apgar score of 6 or less. Analyses used chi 2 test and multiple logistic regression.
Results: The prevalence of 1-minute Apgar scores of 3 or less decreased from 65.9% at 24 weeks to 38.2% at 28 weeks, and the prevalence of 5-minute Apgar scores of 6 or less decreased from 83.3% at 24 weeks to 51.2% at 28 weeks. As the birth weight increased from 500-599 g to 900-1000 g, 1-minute Apgar scores of 3 or less decreased from 77.0% to 39.6%, and 5-minute Apgar scores of 6 or less decreased from 89.2% to 56.4%. Aside from gestational age and birth weight, corticosteroid use was the strongest predictor of Apgar scores above 3 at 1 minute and above 6 at 5 minutes. Male and nonvertex-presenting infants had an increased likelihood of low Apgar scores, as did infants with cord blood pH less than 7.05 or bicarbonate value less than 17 mEq/L.
Conclusion: Neonates at very low gestational ages and birth weights are more likely than larger or more mature infants to have low Apgar scores. Males, nonvertex-presenting infants, and those who are acidotic at birth also have an increased prevalence of low scores. Infants born to mothers treated with antenatal corticosteroids are less likely to have low Apgar scores. This finding indicates that antenatal corticosteroids may benefit the newborn at birth, before respiratory distress syndrome becomes apparent.