It is important to determine whether the failure to thrive results from problems intrinsic to the patient or from problems within the environment. Problems intrinsic to the patient are usually medical problems. Problems within the environment are usually psychosocial. There are multiple causes of failure to thrive that will disturb the body's metabolism enough to result in delayed growth . Psychological and social causes may include emotional deprivation as a result of parental withdrawal, rejection, or hostility.
Economic factors can affect nutrition, living conditions, and parental attitudes.
Environmental factors may include exposure to infections, parasites, or toxins . Sometimes the cause is undetermined. Risk factors for failure to thrive are related to the causes and may include underlying undiagnosed diseases, poverty, negative emotional environments, and crowded or unsanitary living conditions.