Failure to thrive (also referred to as faltering growth) is a medical term that denotes poor weight gain and physical growth failure over an extended period of time in infancy. The term failure to thrive covers poor physical growth of any cause and does not imply abnormal intellectual, social, or emotional development. Infants or children that fail to thrive seem to be dramatically smaller or shorter than other children the same age. Teenagers may have short stature or appear to lack the usual changes that occur at puberty. However, there is a wide variation in normal growth and development.
Failure to thrive can be caused by either an identified medical condition (organic) or environmental factors (nonorganic). Both types are due to inadequate nutrition. In general, the rate of change in weight and height may be more important than the actual measurements. It is important to determine whether failure to thrive results from medical problems or factors in the environment.
Organic: In organic causes of failure to thrive, growth failure is due to an acute or chronic disorder that interferes with nutrient intake, absorption, metabolism, or excretion, or that increases energy requirements. Illness of any organ system can be a cause.
Nonorganic: Up to 80% of children with growth failure do not have an apparent growth-inhibiting (organic) disorder. Growth failure occurs because of environmental neglect (eg. lack of food) or stimulus deprivation.
Lack of food may be due to impoverishment, poor understanding of feeding techniques, improperly prepared formula, or an inadequate supply of breast milk.
Failure to thrive generally means a weight consistently below the 3rd to the 5th percentile for age, a progressive decrease in weight to below the 3rd to the 5th percentile, or a decrease in the percentile rank of two major growth parameters (weight, height, head circumference) in a short period.
Weight is the most sensitive indicator of nutritional status. Reduced linear growth usually indicates more severe, prolonged malnutrition. Because the brain is preferentially spared in protein-energy malnutrition, reduced growth in head circumference occurs late and indicates very severe or long-standing malnutrition.
Prognosis with organic failure to thrive depends on the cause. With nonorganic failure to thrive, 50 to 75% of children older than one year achieve a stable weight above the 3rd percentile. Cognitive function, especially verbal skills, remains below the normal range in about 1/3 of children diagnosed with failure to thrive. Children who develop failure to thrive before one year of age are at high risk, and those diagnosed before age six months of age (when the rate of postnatal brain growth is maximal) are at highest risk. General behavioral problems occur in about 50% of children with previous diagnoses of failure to thrive.
Treatment of failure to thrive aims to restore proper nutrition. A nutritious diet containing adequate calories for catch-up growth (about 150% of normal caloric requirement) and individualized medical and social supports are usually necessary. Hospitalization is rarely required and is indicated for severe failure to thrive only and for those whose safety is a concern.