Faltering growth is characterised by a significant deviation from the expected growth trajectory compared with children of a similar age and gender during early childhood. This term serves as a descriptive label, so it is important to investigate underlying causes. Typically, faltering growth is most commonly observed in young children, particularly infants, rather than in older children or adolescents.

While a temporary weight loss of up to 10% of birth weight is normal in the early days of life, it is typically regained by the age of three weeks once feeding is established. Faltering growth that occurs beyond the neonatal period is characterised by a slower than anticipated rate of weight gain.

Weight faltering is defined as a decline in weight across centile spaces, having a low weight for height, or failing to catch up from a low birth weight. Growth faltering, on the other hand, involves crossing down through length or height centiles in addition to weight, with a specific focus on having a height centile or height below what is expected based on parental heights.