Antecedents and neonatal consequences of low apgar scores in preterm newborns - A population study

Background: To examine the antenatal and early neonatal correlates of low A pgar scores (<3 and <6 at 1 and 5 minutes) in preterm newborns (23-34 weeks ' gestation). Objective: The use of Apgar scoring for premature newborns remains widespre ad, despite controversy regarding its reliability as a measure of morbidity and mortality in the neonatal period. Design: A cohort of 852 preterm newborns born during a 34-month period betw een 1984 and 1987 was studied. Newborns were stratified into 2 groups by ge stational age (23-28 weeks and 29-34 weeks), and data were analyzed, contro lling for gestational age in single weeks. Setting: Two academic and 1 community hospital, which together accounted fo r 83% of all preterm births in a tri-county area of central New Jersey duri ng the study period. Patients: All premature newborns (birth weight <2000 g and gestational age <35 weeks) born in the participating hospitals during the study period were evaluated. Main Outcome Measures: Antecedents included maternal illness during pregnan cy, maternal complications of labor and delivery, and fetal heart rate abno rmalities during labor and delivery. Consequences included delivery room re suscitation, abnormal physical findings, diagnoses, and therapeutic interve ntions in the first 6 to 8 hours of life. Results: Premature newborns with low Apgar scores received more cardiopulmo nary resuscitation in the delivery room and in the first 6 to 8 hours of ne onatal intensive care. Mortality was significantly increased among newborns with low Apgar scores (54% vs 26% in the 23- to 28-week stratum, 30% vs 6% in the 29- to 34-week stratum). Newborns with low Apgar scores in the 29- to 34-week stratum more often required intubation, positive pressure ventil ation, and umbilical vessel catheterization. Newborns with low Apgar scores had higher rates of bradycardia, pneumothoraces, acidosis, and increased o xygen requirement during the first 6 to 8 hours of life. Maternal illness, complications of labor and delivery, and fetal heart rate decelerations did not correlate with subsequent Apgar scores of newborns. The presence of se vere bradycardia (<90/min) and fetal heart rate accelerations correlated wi th low Apgar scores in the 29- to 34-week group. Conclusion: Low Apgar scores are associated with increased neonatal morbidi ty and mortality in preterm newborns. Antenatal maternal history and pregna ncy complications are not clearly associated with low Apgar scores. Therefo re, the Apgar score is a useful tool in assessing neonatal short-term progn osis and the need for intensive care among preterm newborns.