A non-linear model of growth in the first year of life

Weight gain curves in infancy and childhood show valleys and hills which cannot be simplistically ascribed to random variations, so that they are referred to as pulsatile or pulse growth. Classical mathematical models of human growth, upon which the statistical percentiles are based, do not account for these oscillations. Moreover, statistical curves can hide individual patterns of growth. In the present paper a system dynamics approach to modelling the first year weight gain is suggested which simultaneously accounts for the oscillations of weight gain, for its decreasing trend, and for a more or less marked initial spurt observed approximately in the second month of life. It is suggested that the overall weight growth in the first year is the output of complex hidden non-linear dynamics.