Postnatal reference growth curves for very low birth weight infants.

To construct standard growth curves for Japanese infants of very low birth weight (VLBW) with birth weights of 500-1499 g, we reviewed longitudinal data provided by 54 neonatal intensive care units in Japan. A total of 382 surviving singleton infants, appropriate for gestational age infants, and who were free of neurological sequelae at more than 2.5 years of age, were enrolled. Growth curves, including body weight, head circumference and body length were generated for four ranges of birth weight: 500-749 g, 750-999 g, 1000-1249 g, and 1250-1499 g. When compared with previously published growth data from western countries, Japanese infants of VLBW showed greater weight loss, regained birth weight more slowly, and exhibited smaller average gains in weight, head circumference, and body length. The growth curves reported in western countries may not be useful as reference standards of early postnatal growth in Japan. The new growth curves are a more accurate reflection of current in-hospital growth trends in Japan.