Birth weight associated with lowest neonatal mortality: infants of adolescent and adult mothers.

OBJECTIVE: We tested the hypothesis that survival is highest for infants born in the same weight range whether mothers are adolescent or adult, comparing the weights at which infants of these mothers achieve lowest neonatal mortality.
METHODS: The relationship between birth weight and neonatal mortality was studied in births to 16.4 million women using the National Center for Health Statistics 1983-1987 national linked birth/infant death data sets. Neonatal mortality rates were calculated for 500 g birth weight categories. Births for maternal ages < or = 15 years, 16 years, and 17 to 18 years were compared with births to adults 19 to 34 years of age, whites and blacks considered separately. The birth weight categories associated with minimum neonatal mortality and the weight range corresponding with greatest survival were determined for each age and racial group.
RESULTS: Minimum neonatal mortality rates occurred at the same birth weights (3500 to 4499 g white and 3000 to 3999 g black) whether mothers of the infants were adolescents or adults. The most favorable range of birth weight, in which survival was greatest, commenced at 3000 g for all mothers, terminating at 3999 g for most black adolescents and black adults, 4499 g for most white adolescents, and 4999 g for white adults. Of infants born to mothers < or = 16 years old, 33% were lighter and 1.5% were heavier than the favorable birth weight range.
CONCLUSION: The birth weight categories with minimum neonatal mortality and the birth weight range in which neonatal survival was greatest were comparable for infants of adolescents and adults. Lower birth weights, occurring more frequently in births to teenage mothers, were associated with higher neonatal mortality. Assisting adolescent mothers to bear infants with birth weights in the range corresponding with low neonatal mortality is an appropriate goal of clinical management.