Growth Failure Red Flags

Faltering weight describes an infant or young child whose weight gain, or weight relative to length or height, falls below what is expected for age and sex. In 2026 the American Academy of Pediatrics (AAP) replaced the older label failure to thrive with faltering weight because the old term had no precise definition, carried stigma and had unclear standards of care. Families and many Canadian records still say failure to thrive, faltering growth or poor weight gain, so recognize all of these terms. The AAP guideline and its technical reviews focus on children younger than 5 years. Unintentional weight loss in adults is a different problem. The mechanism is an energy and nutrient balance that stays negative over time. Four broad causes, often combined, explain most cases: inadequate intake (too little offered, an ineffective latch, oral-motor or swallowing difficulty, feeding aversion, incorrectly prepared formula or food insecurity); inadequate absorption (for example cystic fibrosis, celiac disease or cholestatic liver disease); excessive losses (persistent vomiting or diarrhea); and increased requirements (for example congenital heart disease, chronic lung disease or chronic infection). The...