Faltering Growth (Failure to Thrive)

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Routine assessments of height and weight should occur throughout childhood and should be plotted on appropriate centile charts. It is important to understand what is a normal growth pattern, when to be concerned, and which children need further investigation.

If a child is not growing as we would expect, this is called failure to thrive or faltering growth. Plotting measurements over time is the most useful way to assess a child’s growth, which is important as it is reflective of their underlying health and nutritional status.1

There are multiple phases of normal growth, with the most rapid rate of growth occurring in the first year of life. Children then grow along a more steady trajectory until the pubertal growth spurt, which is another period of rapid growth that ends when adolescents reach their final height.

The exception to this progressive growth throughout childhood is the first few days of life, where it is considered acceptable to lose up to 10% of birth weight whilst feeding is established.1 80% of babies will have regained birth weight by two weeks of life, but if the weight loss is greater than 10% on day five, or slow to recover, the baby needs clinical assessment and evaluation of feeding.1

After the newborn period, children should grow predictably, and NICE guidelines give thresholds for concern based on measurements plotted on growth charts:2

  • A fall across one or more weight centile spaces, if birth weight was below the ninth centile
  • A fall across two or more weight centile spaces, if birth weight was between the 9th and 91st centiles
  • A fall across three or more weight centile spaces, if birthweight was above the 91st centile
  • When current weight is below the second centile for age, whatever the birth weight
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There are multiple reasons a child might have faltering growth; this is a clinical sign and not a diagnosisΒ and should prompt careful examination and consideration of further investigations.

However, the most common cause of faltering growth is inadequate dietary intake.3

Differential diagnoses

In establishing likely causes for faltering growth, it is important to consider the nutrients which are needed for growth and whether the child has decreased intake, poor absorption, increased losses or a higher-than-normal metabolic demand.1

It is worth remembering that children with certain genetic syndromes (for example Down’s Syndrome, Achondroplasia, DiGeorge Syndrome, Turner’s Syndrome and many others) are not expected to follow the usual patterns of growth as short stature is a part of their condition. For this reason some of these conditions (but not all) have their own growth charts, for example Down’s Syndrome.

Table 1. Causes for faltering growth.

Category Causes

Inadequate nutrient intake

  • Inadequate food provided – social circumstances (e.g. poverty or neglect)
  • Problems with eating – fussiness/food aversions, mechanical problems (e.g. muscle weakness or problems with teeth), swallowing issues (e.g. CNS pathology), feeling of fullness (e.g. constipation, iron deficiency anaemia)
  • Lifestyle – inappropriate nutrient intake (e.g. unbalanced diet, poor parental understanding of requirements)

Inadequate nutrient absorption or increased losses

Increased nutrient requirements or ineffective utilisation

  • Congenital heart disease (e.g. VSD)
  • Malignancy
  • Metabolic diseases (e.g. type one diabetes, hyperthyroidism)
    Chronic inflammation/recurrent infections (e.g. cystic fibrosis)
  • Chronic systemic diseases (e.g. renal failure)


It is important to take a thorough paediatric history, including birth and early neonatal period, history of illnesses, family history of growth concerns and a careful dietary history (a food diary can be useful here).

Asking the straightforward question, β€œIn the past month, was there any day when you or anyone in your family went hungry because you did not have enough money for food?” has been shown to be an effective way to explore food insecurity.4

A full systemic examination is needed to look for evidence of chronic diseases, genetic syndromes or neglect.

Plotting growth

When plotting on centile charts, it is important to ensure the correct chart is used. There are a variety of growth charts appropriate to the child’s gender, age, prematurity (<32 weeks), and some specific medical conditions such as Down’s Syndrome. Always remember to correct for preterm birth until at least one year of age by plotting the measurement at their current age, then drawing a dotted line and an arrow back the number of weeks they were preterm.

Mid-parental height can be calculated, which gives an estimate of the child’s predicted final height (their β€œgenetic potential”):1

  • Males: (mum’s height + dad’s height)/2 + 7cm
  • Females: (mum’s height + dad’s height)/2 – 7cm

If the child’s current height centile is more than two centiles below the mid-parental height centile, this could indicate a problem with growth.1


Once faltering growth has been established, investigations are guided by history and examination findings. Some children may require no investigations if the history points to inadequate nutrient intake which can be remedied, although consequences of poor intake such as vitamin D and iron levels might be considered.1Β 

First line tests looking for medical causes would include FBC, blood film, iron studies, vitamin D levels, U&E, LFT, inflammatory markers and tTG.


Dietary advice and advice about mealtimes with children should be given, and the child should be seen again after an appropriate interval (shorter in younger children) to reassess and plot further measurements.1

Some children require a dietician referral, especially if they are particularly fussy eaters or have food aversions. If these strategies are unsuccessful, the child should be referred to secondary care for further assessment.

Advice around mealtimes for children1
  • Mealtimes should be relaxed and enjoyable
  • Balanced, nutritional meals should be offered
  • Ideally children should eat with the family- parents and/or other children
  • Young children should be encouraged to feed themselves, even if this is messy
  • Mealtimes should not be too brief or too long
  • Reasonable boundaries should be set for mealtime behaviour (while avoiding punitive approaches)
  • Coercive feeding should be avoided
  • There should be regular eating schedules (for example three meals and two snacks in a day)


Globally, up to one-third of children are not thriving due to malnutrition.5 This can lead to permanent short stature, as well as systemic complications such as immunodeficiency or damage to the growing brain, which can lead to behavioural difficulties and poorer developmental and cognitive outcomes.6,7

Key points

  • Failure to thrive/faltering growth is common and is most often related to under-nutrition
  • Multiple measurements plotted accurately over time is the best way to spot concerning trends in a child’s growth, which can then be investigated
  • It is important to consider food insecurity and neglect as well as investigating for medical causes
  • Simple dietary and lifestyle advice will be effective in most cases


  1. Harris DB. Faltering growth. InnovAiT. 2024;0(0). doi:10.1177/17557380241246244
  2. NICE (2017) Overview. Faltering growth: Recognition and management of faltering growth. Available from: [LINK]
  3. Homan GJ (2016) Failure to thrive: A practical guide. American Family Physician 94(4): 295–299.
  4. Kleinman RE, Murphy JM, Wieneke KM, et al. (2007) Use of a single-question screening tool to detect hunger in families attending a neighborhood health center. Ambulatory Pediatrics: The Official Journal of the Ambulatory Pediatric Association 7(4): 278–284.
  5. UNICEF (2019) The state of the world’s children 2019. Children, food and nutrition: Growing well in a changing world. Available from: [LINK]
  6. Perrin EC, Cole CH, Frank DA, et al. (2003) Criteria for determining disability in infants and children: Failure to thrive: Summary. In: AHRQ Evidence Report Summaries. Rockville, MD: Agency for Healthcare Research and Quality (US); 1998–2005, p. 72.
  7. Corbett SS and Drewett RF (2004) To what extent is failure to thrive in infancy associated with poorer cognitive development? A review and meta-analysis. Journal of Child Psychology and Psychiatry 45(3): 641–654.


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