Non-linear patterns of growth in very low birth weight infants

The deviations of daily weight, weekly length and head circumference from Linear growth were analyzed in 87 very low birth weight infants. The deviations exhibited a highly significant polynomial oscillation not only for weight, but also for length and head circumference. The weight amplitudes were larger for males than for females. They were also larger in infants appropriate for gestational age than in small-for-date infants. The difference with trophicity may be related to the process of adjustment of catch-up in small-for-date infants. However, the mechanisms of these oscillatory deviations could also be explained by clinical events, method of feeding, or homeostatic regulation. Further studies are required to elucidate the role of the different factors. (C) 1998 Wiley-Liss, Inc.