A description applied to children whose current weight or rate of weight gain is significantly below that of other children of similar age and sex (typically weight for age below the fifth percentile or which crosses two main percentile lines on a standard growth curve). A relatively common condition, particularly in the first six months, with different etiologies, it has been associated with adverse effects on both later growth and cognitive development. Its causes are either organic or non-organic, although in practice this is not useful distinction as most children have mixed aetiologies. Thus, for example, not only inadequate caloric intake or lactose intolerance have to be taken into consideration, but also stress and psychosocial factors (e.g., parental neglect or hyper vigilance). Preterm infants, especially those with intrauterine growth restriction, run a risk of showing the signs of failure to thrive.
See Etiology, Intrauterine growth retardation or restriction (IUGR), Intolerance for cow‚was milk protein, Preterm infant