Growth of Infants and Young Children Born Small or Large for Gestational Age - Findings from the Third National Health and Nutrition Examination Survey

Objectives: To compare the growth profiles of infants and young children bo rn small for gestational age (SGA, <10th percentile birth weight for gestat ion) or large for gestational age (LGA, greater than or equal to 90th perce ntile) with those appropriate for gestational age, and to document the expe cted growth patterns through early childhood based on national health exami nation survey data. Sample: Infants and children, 2 to 47 months of age, who were born in the U nited States and examined using the Third National Health and Nutrition Exa mination Survey (1988-1994). Main Outcome Measures: Measurements of growth status based on normalized di stributions (z scores or standard deviation units [SDUs] for weight, length , and head circumference. Results: Prevalence rates were as follows: SGA infants, 8.6%; appropriate f or gestational age infants, 80.9%; and LGA infants, 10.5%. Infants who were SGA appeared to catch up in weight in the first 6 months, but thereafter m aintained a deficit of about -0.75 SDUs compared with infants who were appr opriate for gestational age. The weight status of LGA infants remained at a bout +0.50 SDUs through 47 months of age. Length and head circumference wer e also associated with birth weight status, averaging over -0.60 SDUs for S GA infants and +0.43 SDUs for LGA infants. Conclusions: Birth weight status is related to growth rates in infancy and early childhood, which underscores the importance of considering child grow th relative to birth status when using growth charts. Small for gestational age infants remain shorter and lighter and have smaller head circumference s, while LGA infants grow longer and heavier and have larger head circumfer ences.