Growth status and growth rates of a varied sample of low birth weight, preterm infants: a longitudinal cohort from birth to three years of age.

To obtain follow-up growth data on a large sample of low birth weight, preterm infants, 985 infants were monitored longitudinally in an eight-site collaborative program until 3 years of age, corrected for prematurity. The growth of 608 of these infants was described previously through 1 year of age. In the full sample, 149 infants weighed less than or equal to 1250 gm at birth, 474 between 1250 and 2000 gm, and 362 between 2000 and 2500 gm. Thirty-three percent were white, 53% were black, and 11% were Hispanic. Weight, length, and head circumference were measured at birth and at 40 weeks and 4, 8, 12, 18, 24, 30, and 36 months gestation-corrected age in at least 862 infants each time. Descriptive statistics and estimated growth rates for all growth variables and a body mass index (height in kilograms per square meter), plotted by sex and birth weight group, demonstrated growth patterns lower than published standards for term infants of the same age and sex. These patterns of growth differed by birth weight group. Little catch-up was noted by the 36-month examination for gestation-corrected age for any birth weight group. We conclude that low birth weight, preterm infants have different patterns of growth than term infants during the first 3 years of life, even with plotting corrected for gestational age.