Failure to Thrive


FTT Definition

  • Refers to infants whose weight is less than the norms for their gestation corrected age, sex, genetic potential, and medical condition.
  • Does not include infants and kids with genetic short stature, constitutional growth delay, prematurity, or IUGR who have appropriate weight for length and normal growth velocity.
  • There is no consensus regarding the specific definition, but is attributed to an infant or child who, over time, has any of the following:
    • Weight below the 3rd or 5th % for gestation corrected age and sex
    • Weight less than 80% of ideal weight for age
    • Depressed weight for length
    • A rate of weight gain that causes a decrease in two or more major percentile lines (75th to 25th) over less than 6 months
    • A rate of daily weight gain less than that expected for age


Normal growth in infants

  • Average birth weight = 3.3kg
  • Weight drops as much as 10% in first few days of life (likely due to loss of excess fluid)
  • Birth weight should be gained back by 10 days of age. Birthweight should be doubled by age 4 months and tripled by age 12 months.
  • On average, infants gain:
    • 26-31grams per day from 0-3 months
    • 17-18 grams per day from 3-6 months
    • 12-13 grams from 6-9 months
    • 9-13 grams per day from 9-12 months
    • 7-9 grams per day from 1- 3 years
  • Length increases by:
    • 25cm during the 1st year
    • 12.5 cm in the 2nd year
    • 5-6cm/year between 4 years old and puberty
    • Up to 12cm/year around puberty
  • Head circumference average at birth = 35cm
    • Head circumference increases, on average, to:
      • 47 cm by age 1 year
      • 55 cm by age 6 years


  • Depends on the population sampled.
  • 5-10% of low-birth weight children and children living in poverty have FTT.

Potential implications

  • Persistent short stature
  • Secondary immune deficiency
  • Increased susceptibility to infection, establishing an infection-malnutrition cycle since illness decreases appetite and nutrient intake, which leaves the child vulnerable to severe or prolonged infections
  • Permanent damage to various parts of the brain and CNS


  • Based upon Pathophysiology
    • Inadequate intake
    • Inadequate absorption or increased losses
    • Increased requirements (excess metabolic demand)
    • Defective utilization

Differential Diagnosis

There are many different ways to classify failure to thrive. Focus on which one works best for you.

By age of onset

Prenatal Neonatal (<1 mos) 3 – 6 mos 7 – 12 mos >12 mos
– IUGR- Prematurity- Prenatal infxn

– Congenital syndromes

– Teratogenic exposures

– Psychosocial- Poor quality of suck- Incorrect formula preparation

– Breastfeeding problems

– Inadequate number of feedings

– Poor feeding interactions (eg infant gags or vomits during feeds, mom misreads signals of hunger or satiety)

– Neglect

– Inborn errors of metabolism

– Chromosomal

– Anatomic abnormalities

– Psychosocial- Underfeeding- Improper formula preparation

– Milk protein intolerance

– Oral motor dysfunction

– Celiac disease

– CF




– Inborn errors of metabolism

– Renal tubular acidosis

– Psychosocial- Oral motor dysfunction that interferes with eating more textured foods- Delayed introduction of solids

– Intolerance of new foods

– Intestinal parasites

– Renal tubular acidosis

– New psychosocial stressor (divorce, job loss, new sibling, death in family)- Coercive feeding- Highly distractable child

– Distracting environment

– Acquired illness

By Pathophysiology

Inadequate Nutrient Intake Inadequate Nutrient Absorption or Increased Losses Increased Nutrient Requirements or Ineffective Utilization
– Inappropriate feeding technique*- Economic deprivation- Inappropriate nutrient intake (ie excess juice intake)*

– Insufficient lactation*

– Gastroesophageal reflux*

– Psychosocial problems*

– Mechanical problems (ie. cleft palate, dental lesions)

– Sucking/swallowing dysfunction*

– Central nervous system dysfunction* (ie. cerebral palsy, hypotonia)

– Genetic syndromes

– Inadequate appetite (ie. anorexia of chronic disease, chemotherapy, chronic constipation)

– Inability to eat large amounts* (ie. cardiopulmonary disease)

– Malabsorption*:- cystic fibrosis- cardiac disease

– milk allergy

– inflammatory bowel


– celiac disease

– parasites

– short gut syndrome

– Biliary atresia/cirrhosis

– Vomiting

– gastroenteritis

– increased intra-

cranial pressure

– adrenal insufficiency

– Intestinal tract


– pyloric stenosis

– hernia

– malrotation

– intussusception

– Infectious diarrhea

– Hyperthyroidism- Malignancy*- Congenital or acquired heart disease*

– Chronic inflammatory bowel disease

– Chronic systemic disease (ie. SLE, idiopathic juvenile arthritis)

– Chronic or recurrent systemic infections (ie. tuberculosis, recurrent urinary tract infections)

– Chronic respiratory insufficiency (ie. bronchopulmonary dysplasia, cystic fibrosis)*

– Chronic metabolic disorder (ie inborn error of metabolisms, storage diseases, diabetes mellitus, adrenal insufficiency)

*common causes

By Organic Causes

GI GERD, celiac disease, pyloric stenosis, cleft palate/lif, lactose intolerance, Hirschsprung disease, milk protein intolerance, necrotizing enterocolitis or short-gut syndrome, liver disease, cirrhosis, pancreatic insufficiency, biliary disease, inflammatory bowel disease, malabsorption, food alkalines
Renal UTI, renal tubular acidosis, diabetes insipidus, chronic renal insufficiency
Cardiopulmonary CHD, cardiac diseases leading to CHF, asthma, bronchpulmonary dysplasia, CF, anatomic abnormalities of upper airway, obstructive sleep apnea (snoring)
Endocrine Hypothyroidism, hyperthyroidism, DM, adrenal insufficiency or excess, parathyroid disorders, pituitary disorders, growth hormone deficiency
Neurologic Mental retardation, cerebral hemorrhages, degenerative disorders, CN palsy, Arnold- Chiari malformation
Infectious Parasitic or bacterial infections of GI tract, TB, HIV
Metabolic Inborn errors of metabolism
Congenital Chromosomal abnormalities, congenital syndromes (FAS), perinatal infections
Miscellaneous Lead poisoning, malignancy, collagen vascular disease, recurrently infected adenoids and tonsils, malignancy, Rickets

Psychosocial Causes

  • Poor or inappropriate diet for age
  • Eg excessive use of fruit juice
  • Improper formula preparation
  • Diluted or over-concentrated
  • Food fads and special diets, including applying diets for adults to kids
  • Parental neglect
  • Poverty or financial stressors leading to food shortage
  • Oral aversion
  • Food phobia
  • Parental mental health problems
  • Parental eating disorders
  • Child abuse


Risk Factors

Medical Psychosocial
PrematurityDevelopmental delayCongenital anomalies (eg cleft lip and/or palate)

Intrauterine exposures (eg alcohol, anticonvulsants, infxn)

Lead poisoning


PovertyCertain health and nutritional beliefs (eg fear of obesity or CV disease, prolonged exclusive breastfeeding)Social isolation

Life stresses

Poor parenting skills

Disordered feeding techniques

Substance abuse



Important information to obtain on history

  • Mood and belief systems of parents?
    • Screen for parental depression
    • Unusual dietary beliefs
    • Lack of knowledge
    • Relationship to the child
      • Get a sense of how much time they spend together, how much cuddling?
  • Financial situation?
    • Can the parents afford appropriate/enough food?
  • Detailed dietary history
    • Breastfeeding and/or formula history?
      • Any problems, changes?
      • How do you know when the infant has had enough?
      • Breastfeeding technique?
      • Type of formula? How is it prepared? How much per day?
      • Is the baby held when fed? Eye contact? Enjoyable experience?
      • Issues with vomiting? Spitting up? Reflux?
      • Is there any sweating with feeds?
    • What foods/drink does the diet consist of?
      • Have solids been introduced? If so when?
      • How much does the infant/child eat?
      • Snacking?
    • How often is the infant/child fed?
    • Where does eating take place?
      • At table or in front of television?
  • Physical function
    • Frequent illnesses?
    • Symptoms of heart/respiratory disease?
    • Does the infant/child appear to have difficulty swallowing?
    • Any anatomic abnormalities?
    • Stool function?
      • Frequency, color, consistency?
    • Vomiting/spitting up?
  • Change in infant/child’s behavior
    • Fatigue?
    • Decreased energy (not as active as usual)?
  • Developmental history?
    • Slow compared to other infants/kids?
    • Speech?
    • Gross Motor function? (rolling over, crawling, walking)
    • Fine motor function?
    • Adaptive function?
  • Prenatal history
    • Health concerns during the pregnancy?
    • Any exposures? (smoke, alcohol, other drugs)
    • Complications with delivery?
  • Family history

Physical Exam

Evaluation of proportionality

  • Decreased weight in proportion to length
    • Reflects inadequate nutritional intake
  • Decreased length in proportion of weight
    • Suggestive of an endocrinologic abnormality
  • Decreased length with a proportionate weight
    • May be nutritional, genetic, or endocrine in origin
  • Head circumference impaired as much as, or more than, weight or length
    • Suggestive of an intrauterine infection, teratogenic exposures, congenital syndromes, or other causes of microcephaly

Physical findings


  • Loss of subcutaneous fat
  • Reduced muscle mass
  • Marasmus
  • Kwashiorkor


  • Dysmorphic features
  • Shape of head
  • Fontanelles
  • Sutures
  • Oral abnormalities
  • Enlarge tonsils

Cardiac and pulmonary

  • Cyanosis
  • Clubbing
  • Resp distress
  • Dusky skin
  • Murmurs


  • Abdo distention
  • Orangomegaly
  • Masses


  • Detailed exam looking for any deficits


  • Dermatitis
  • Alopecia
  • Jaundice
  • Dry, scaly skin



  • This is a vital tool for picking up failure to thrive à look at the pattern of growth over time

Initial screen (often not indicated)

  • CBC
  • Lytes, renal function, albumin
  • Lead level
  • Urinalysis

Further investigations depending on clinical picture

  • Bone age
  • Thyroid function studies
  • Tests for GERD, malabsorption, celiac, or CF
    • Stool analysis
    • Sweat test
    • TTG-IGA
  • Liver enzymes
  • Infectious work-up: urine, stool, respiratory and/or blood cultures
  • HIV, TB investigations
  • GH def
    • IGF-1


Failure to thrive is a common pediatric presentation. Working through your differential diagnosis by pathophysiology will help guide your history, physical examination, investigations and management. Always remember that growth parameters are part of your pediatric physical examination!


Bergman I. “Failure to Thrive” in Nelson Textbook of Pediatrics, 17th Ed. (2004). Chapter 35. Saunders, Philadelphia.

Frangiskakis, S; McIntire, S; and Scherger, E. First Consult. “Failure to Thrive.” Last updated 15 Dec 2005.

Bassali, R and Benjamin, J. eMedicine. “Failure to Thrive”. Last updated 25 April, 2006., online version 13.1. Etiology and evaluation of failure to thrive (undernutrition) in children younger than two years.


Written by: Lara Malks-Jjumba

Edited by: Anne Marie Jekyll

One response to “Failure to Thrive”


    Failure to thrive.. Super 🙂

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