lack of expected normal physiological development in childhood failure to thrive UMLS_ICD9CM_2005_AUI:A0700791 symptoms SYMP:0000465 UMLS_CUI:C0015544 A lack of expected normal physiological development in childhood that is characterized by a decelerated or arrested physical growth (height and weight measurements fall below the third or fifth percentile, or a downward change in growth across two major growth percentiles) and is associated with abnormal growth and development. ICD9CM_2005:783.41