Approaches to detecting growth faltering in infancy and childhood

One of the purposes of monitoring a child's weight or height is to detect growth faltering. In infancy the focus is on monitoring weight gain, primarily for detecting infants at risk of failure-to-thrive. In childhood, this switches to height gain, e. g. the response of a child that is growth hormone deficient to treatment with growth hormone. Cross-sectional charts provide no guidance in a longitudinal context. If we note the current weight or height of a child, but want to say something about a child's growth since the last weight and height measurement, we need to use a velocity/increment reference or take a conditional approach to the problem. Here we focus on growth faltering and review the mathematical approaches to this problem. Discussion will concentrate on the relative merits of the following approaches: velocity references and increment charts or tables; conditional gain Z-scores; infancy weight-monitoring charts and longitudinal growth norms implemented in the growth package LGROW; tracking indices and distance charts and centile crossing. Overall conditional gain Z-scores provide the most flexible means of assessing growth patterns.