THE APGAR SCORE AND ITS COMPONENTS IN THE PRETERM INFANT

Objective. The Apgar score is well-characterized in full-term infants but not in premature infants. The objective of this study was to asses s the Apgar score in preterm infants with respect to the relationships between the 1- and 5-minute scores, the correlation of the Apgar scor e with pH and with other variables, and the relationship among the ind ividual Apgar components. Methodology. We recorded Apgar scores at 1 a nd 5 minutes in a population-based cohort of preterm infants (n = 1105 ) with birth weight <2000 g, from three intensive care nurseries in ce ntral New Jersey. Linear correlation analysis was used to examine the relationship between 1- and 5-minute Apgar scores and between the indi vidual components of the Apgar score. Multiple regression analysis was used to explore the relationship between various perinatal characteri stics and the Apgar score, and between pH and Apgar score. Stepwise lo gistic regression analysis was used to assess the determinants of mort ality. Results. The 1-minute Apgar score median (25%, 75%) was 6(4,8) and correlated with the 5-minute score of 8(7,9) at r = .78. Slight bu t significant differences were seen between male (n = 557) and female (n = 508) infants in the 1-minute (6[4,8] and 7[4,8]) Apgar scores. On e-and 5-minute scores of white infants (7[4,8] and 8[7,9]; n = 713) we re significantly higher than those of black infants (5[3,7] and 8[6,9] ; n = 280). Birth weight and gestational age were both linearly relate d to both Apgar scores. Low Apgar score (<3 at 1 minute and <6 at 5 mi nutes) was significantly associated with birth weight, gestational age and mode of delivery. Low arterial blood pH (<7.01) at birth was sign ificantly related to low Apgar score. One hundred fifty-nine infants d ied; these infants were significantly smaller (983 +/- 382 vs 1462 +/- 369 g), less mature (27 vs 31 weeks), had lower arterial blood pH (7. 20 +/- 0.18 vs 7.31 +/- 0.11), had lower 1-(3[2,6] vs 7[4,8]) and 5-mi nute Apgar scores (6[4,8] vs 8[7,9]), and a greater incidence of low A pgar score (32% vs 6%) than did survivors. Conclusions. Among the comp onents of the Apgar score, respiratory effort, muscle tone, and reflex activity correlated well with one another; heart rate correlated less well; and color the least. Our data confirms the limited use of the A pgar score in preterm infants and demonstrates the different responses of the Apgar score's components.