Weight-for-Length Reference Data for Preterm, Low-Birth-Weight Infants

Abstract

OBJECTIVE: To provide weight-for-length reference data for preterm, very-low-birth-weight and low-birth-weight infants. DESIGN: Data from 867 infants (428 boys and 439 girls) in the Infant Health and Development Program, who each were preterm and who had a low birth weight, were used to develop weight-for-length reference data. The Infant Health and Development Program is a national, randomized, clinical trial that included various ethnic groups at 8 sites. At each site, sampling ensured that two thirds of the infants in the study weighed 2000 g or less and that one third of the infants weighed from 2001 to 2500 g at birth. Infants were examined at birth, at 40 weeks' postconception, and at 4, 8, 12, 18, 24, 30, and 36 months' gestation-adjusted age. Gestation-adjusted age was used instead of chronological age from birth to correct for the degree of prematurity. RESULTS: Weight-for-length percentiles are given for lengths at 3-cm intervals ranging from 48 to 100 cm. These percentiles are sex specific and are for a very-low-birth-weight group (< or = 1500 g) and a low-birth-weight group (1501-2500 g). CONCLUSIONS: These data should assist screening for deviations from normal growth and may aid in the early detection of failure to thrive and excessive weight gain in infancy.