Early postnatal growth of low birthweight infants in the WIC program

Patterns of early postnatal growth were analyzed among low birthweight infa nts enrolled in the Special Supplemental Nutrition Program for Women, Infan ts, and Children (WIC). Infants were divided into four groups according to their neonatal status: (1) term, normal birthweight (NBW); (2) term, low bi rthweight (LBW); (3) moderately preterm LBW; and (4) very preterm LEW. Comp arison of mean weight and length z-scores indicated that term NEW and very preterm LEW infants were at or near the national reference averages at 8, 1 2, and 18 months. Term LEW and moderately preterm infants were lighter and shorter than the other two study groups at each visit. Term LEW and moderat ely preterm infants displayed evidence of catch-up growth during the study period. Catch-up growth was defined as a decrease in the percentage of infa nts below the 10th percentile for weight. The effect of neonatal body propo rtions on postnatal growth was investigated in term LEW infants. The infant s were divided into two groups based on their ponderal index (PI) at birth (low PI and proportionate PI). Comparison of weight and length z-scores ind icated that both groups of term LEW infants improved in z-scores between bi rth and the first visit (approximately 8 months). However, infants with evi dence of asymmetric intrauterine growth restriction (low PI) continued to i mprove in weight and length z-scores, whereas those with symmetric growth r estriction (proportionate PI) remained lighter and shorter. Am. J. Hum. Bio l. 13:261-267, 2001. (C) 2001 Wiley-Liss, Inc.