Growth patterns of low-birth-weight infants: 2-year longitudinal study

A 2 year longitudinal study of the growth of 147 low birthweight (LBW) < 2,500 g infants who had no known factors disturbing growth was conducted. The infants were divided into 6 groups according to birthweight and maturity: group 1--appropriate for gestational age (AGA) with birthweight < 1,500 g (n = 18); group 2--AGA 1,500-1,999 g (n = 41); group 3--AGA 2,000-2,499 g (n = 26); group 4--small for gestational age (SGA) < 1,500 g (n = 5); group 5--SGA 1,500-1,999 g (n = 20); group 6--SGA 2,000-2,499 g (n = 37). The control group consisted of 149 normal birthweight (> 2,500 g) infants. Weight, height, and head circumference were measured at birth, 2, 4, 6, 9, 12, 18, and 24 months postnatally and recorded in standard deviation score (SDS). All groups showed catch-up growth in the first 6 months. At 2 years old, all infants were above -2 SDS. However, the SGA infants with birthweight < 1,500 g were significantly lighter (-0.9 SDS, p = 0.003), shorter (-0.6 SDS, p = 0.001) and had smaller head size (-0.65 SDS, p = 0.027) whereas, the other groups were not different compared to the control group. We also compared those LBW infants who, at 2 years of age, weighed below -1 SDS to those who weighed above -1 SDS and found no significant difference in familial income, parental education, nursing care or parental height. We concluded that with adequate nutritional intake and nursing care, LBW infants have the potential for good catch-up growth. For the SGA infants with birthweight < 1,500 g, although they showed good catch-up growth, they still remained smaller than their peers at 2 years of age.