Assessment of postneonatal growth in VLBW infants: selection of growth references and age adjustment for prematurity.

OBJECTIVES To assess growth outcomes of VLBW infants using different growth references and to validate the practice of age adjustment for prematurity in the growth assessment for VLBW infants. METHODS Longitudinal growth data of 514 VLBW infants from 4 to 36 months of adjusted age were analyzed separately based on chronological and adjusted age and by comparison with three growth references. RESULTS More infants were labelled as having "subnormal growth" assessed on chronological age than on adjusted age throughout the first three years of life. The proportions of subnormal growth determined using a Canadian and the WHO reference for breastfed infants were similar; they were different from those obtained using the NCHS/WHO reference. CONCLUSIONS Our findings suggested that the interpretations of growth in VLBW infants vary substantially depending on which reference is used. The age adjustment for prematurity makes substantial difference in identifying subnormal growth in VLBW infants. The adjustment should be carried out throughout the first three years of life.