Failure to Thrive in Infancy: Anthropometric Definitions

Abstract

The term Failure to Thrive (FTT) has been widely used during the last century to describe poor growth in early childhood. The condition has traditionally been classified on the basis of the presence or absence of somatic illness, with most cases being of non-organic or mixed origin. In early literature definitions of FTT included emotional and behavioural symptoms, which strongly linked the condition to maternal deprivation and psychosocial adversity. However, a consensus in 1985 concluded that the primary identification of FTT must be based solely on anthropometric parameters. Albeit, there is no consensus about a specific anthropometric definition, and a broad range of different anthropometric indicators and cut-off points have been used to identify FTT. Most criteria have been based on weight measures, equalling FTT with slow weight gain, and FTT have thus for example been defined as weight falling below the 3rd percentile, downward crossing of weight over two or more main percentile lines, and weight gain below the 5th percentile conditioned on birth weight taking into account the normal phenomenon of regression towards the mean. The concurrence between different criteria of FTT, however, is low, and different criteria are likely to identify different child populations with different risks of adverse outcome. Thus, during the last decade it has been suggested that this rather vague term should be abolished in favour of more valid anthropometrical descriptions based on explicit measures of growth or nutritional status.