Failure to Thrive

Failure to thrive refers to poor physical growth and development in a child. Faltering growth is defined in the 2017 NICE guidelines on faltering growth in children as a fall in weight across:

  • One or more centile spaces if their birthweight was below the 9th centile
  • Two or more centile spaces if their birthweight was between the 9th and 91st centile
  • Three or more centile spaces if their birthweight was above the 91st centile

Centile spaces are the distance between two centile lines on a growth chart. The distance between the 75th and 50th centile lines is a centile space. A weight that falls this distance is a drop across one centile space. For example, if the initial weight of a child is plotted halfway between the 9th and 25th centile lines and several months later is plotted halfway between the 2nd and 9th centile lines, they have dropped a full centile space.


Causes of Failure to Thrive

Anything that leads to inadequate energy and nutrition can lead to failure to thrive. The causes can be categorised as:

  • Inadequate nutritional intake
  • Difficulty feeding
  • Malabsorption
  • Increased energy requirements
  • Inability to process nutrition


Causes of Inadequate Nutritional Intake

  • Maternal malabsorption if breastfeeding
  • Iron deficiency anaemia
  • Family or parental problems
  • Neglect
  • Availability of food (i.e. poverty)


Causes of Difficulty Feeding


Causes of Malabsorption


Causes of Increased Energy Requirements


Inability to Process Nutrients Properly



The aim of assessment is to establish the cause of the failure to thrive. This involves taking a full history, examining the child and completing relevant investigations. Key areas need to be assessed:

  • Pregnancy, birth, developmental and social history
  • Feeding or eating history
  • Observe feeding
  • Mums physical and mental health
  • Parent-child interactions
  • Height, weight and BMI (if older than 2 years) and plotting these on a growth chart
  • Calculate the mid-parental height centile

A feeding history involves asking about breast or bottle feeding, feeding times, volume and frequency and any difficulties with feeding. An eating history involves asking about food choices, food aversion, meal time routines and appetite in children. Asking the parent to keep a food diary can be helpful.

BMI is calculated as: (weight in kg) / (height in meters)2.

Mid parental height is calculated as: (height of mum + height of dad) / 2.

Outcomes from the assessment that would suggest inadequate nutrition or a growth disorder are:

  • Height more than 2 centile spaces below the mid-parental height centile
  • BMI below the 2nd centile



NICE guidelines from 2017 on faltering growth recommend the following initial investigations:

  • Urine dipstick, for urinary tract infection
  • Coeliac screen (anti-TTG or anti-EMA antibodies)

Further investigations are usually not necessary where there are no other clinical concerns. Focused investigations should be considered where additional signs or symptoms suggest an underlying diagnosis, such as cystic fibrosis or pyloric stenosis.



Management depends on the cause and may involve input from the multidisciplinary team. All children with faltering growth should have regular reviews to monitor weight gain. Reviews that are too frequent can increase parental anxiety.

Where difficulty with breastfeeding is the cause, there are lots of ways for the mother to get support, including midwives, health visitors, peers groups and “lactation consultants”. Supplementing with formula milk is likely to successfully improve growth, however it often results in breastfeeding stopping. Mother should be encouraged to feed with breastmilk prior to top-up feeds, and express when not breastfeeding to encourage lactation to continue.

Where inadequate nutrition is the cause there are several management options based on individual circumstances:

  • Encouraging regular structured mealtimes and snacks
  • Reduce milk consumption to improve appetite for other foods
  • Review by a dietician
  • Additional energy dense foods to boost calories
  • Nutritional supplements drinks

Where other measures fail and there are serious concerns the multidisciplinary team may consider enteral tube feeding. This needs to have clear goals and a defined end point.


Last updated January 2020
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