Boston University School of Medicine, Massachusetts.
Malnutrition is the primary biologic insult in most cases of failure to thrive. A transactional model of infant development provides a framework for understanding the psychosocial context in which such malnutrition occurs. Each child who fails to thrive should receive a multidisciplinary evaluation to address the diagnostic and therapeutic implications of nutritional, medical, psychosocial, and developmental factors contributing to growth failure.