Key Facts

Faltering growth (failure to thrive) describes a child whose weight gain is inadequate compared to expected norms. It is a sign rather than a diagnosis and requires systematic evaluation to identify the underlying cause. The majority of cases are due to inadequate caloric intake rather than organic disease.

Epidemiology

Faltering growth affects approximately 5% of children under 5 years presenting to primary care or health visitor review. It is more common in areas of socioeconomic deprivation. Most cases present in the first 2 years of life. Boys and girls are equally affected.

Aetiology

Non-organic (inadequate intake): Insufficient milk/food offered, feeding difficulties, poverty, neglect, maternal mental health problems, disordered parent-child feeding interaction.

Organic causes:

• Inadequate intake: Cleft palate, GORD, oral motor dysfunction
• Malabsorption: Coeliac disease, cystic fibrosis, cow's milk protein allergy, inflammatory bowel disease
• Increased requirements: Chronic heart failure (CHD), chronic lung disease, hyperthyroidism, malignancy
• Increased losses: Chronic diarrhoea, proteinuria (nephrotic syndrome)
• Endocrine: Growth hormone deficiency, hypothyroidism, Turner syndrome

Pathophysiology

Inadequate caloric intake relative to metabolic requirements leads to utilisation of fat stores and eventually muscle mass. Weight is affected first, then linear growth (length/height), and finally head circumference if deprivation is severe and prolonged. Chronic undernutrition impairs immune function, cognitive development, and may cause long-term neurodevelopmental consequences.

Presenting Features

• Weight falling across 2 or more centile lines on the UK-WHO growth chart
• Weight below the 2nd centile (especially if birth weight was higher)
• Visible wasting, reduced subcutaneous fat
• Irritability, apathy, developmental delay (in severe cases)
• Delayed milestones

Feeding History Clues

• Inadequate volume or frequency of feeds
• Prolonged mealtimes with refusal or distress
• Inappropriate diet for age (e.g., excessive juice, restrictive diet)
• Breastfeeding difficulties (poor latch, low supply)

Psychosocial Factors

• Maternal depression or mental illness
• Domestic abuse, substance misuse
• Social isolation, poverty
• Neglect (consider safeguarding)

Red Flags

• Weight below 2nd centile and falling
• Severe wasting or dehydration
• Developmental regression
• Features suggestive of neglect or abuse — safeguarding referral
• Dysmorphic features suggesting genetic syndrome
• Persistent vomiting, chronic diarrhoea, or blood in stool — organic cause

Bedside

• Accurate growth measurements: Weight, length/height, head circumference plotted on UK-WHO growth charts (RCPCH)
• Developmental assessment: Gross motor, fine motor, speech, social milestones
• Feeding observation: Direct observation of a feed if possible
• Dietary history: Detailed 3-day food diary

Bloods

• Not routinely required if non-organic cause is likely (NICE NG75)
• If organic cause suspected:
  • FBC, ferritin, folate, B12: Anaemia, nutritional deficiencies
  • U&Es, creatinine: Renal disease
  • LFTs: Liver disease
  • TFTs: Hypothyroidism
  • Coeliac screen (tTG-IgA): Coeliac disease
  • Calcium, phosphate, vitamin D: Rickets, metabolic bone disease
  • Immunoglobulins: Immunodeficiency

Imaging

• Not routinely indicated
• Bone age (wrist X-ray): If growth hormone deficiency or constitutional delay suspected
• Echocardiography: If cardiac murmur or signs of heart failure

Special Tests

• Sweat test: If cystic fibrosis suspected
• Karyotype: If dysmorphic features (Turner syndrome, other genetic syndromes)
• Urine metabolic screen: If metabolic disease suspected

Non-pharmacological

• Dietetic assessment and intervention: Increase caloric density of feeds/food; high-energy supplements if needed
• Feeding advice: Age-appropriate feeding schedule, structured mealtimes, positive feeding environment
• Breastfeeding support: Lactation consultant if breastfeeding difficulties
• Health visitor intensive support: Regular weight monitoring (weekly initially)
• Psychosocial support: Address maternal mental health, refer to social services if safeguarding concerns
• Treat underlying cause: GFD for coeliac, CMPA elimination diet, GORD treatment etc.

Pharmacological

• Nutritional supplements: Calorie-dense formula feeds (e.g., Infatrini, SMA High Energy) for infants
• Vitamin and mineral supplementation: Iron, vitamin D as guided by deficiencies
• Treat organic cause: Anti-reflux medications (omeprazole 0.7mg/kg OD), pancreatic enzyme replacement (Creon) for CF

Surgical/Interventional

• Nasogastric feeding: If oral intake remains insufficient despite intervention
• Gastrostomy (PEG/button): For prolonged feeding difficulties (e.g., neurodisability, severe organic disease)

Referral Criteria

• Weight below 2nd centile and falling despite community intervention — paediatric referral
• Suspected organic cause — paediatric gastroenterology, endocrinology, or cardiology as appropriate
• Safeguarding concerns — social services and safeguarding team
• Severe faltering with developmental impact — multidisciplinary team assessment

• Non-organic FTT: Majority respond well to dietary intervention and support; catch-up growth within 3-6 months
• Organic causes: Prognosis depends on the underlying condition
• Long-term outcomes: Persistent FTT in early life associated with lower IQ scores (2-4 points), behavioural difficulties, and shorter adult height
• Severe malnutrition: If prolonged (>6 months), may cause permanent cognitive impairment
• Safeguarding cases: Outcomes improve significantly with early intervention and family support
• Most children with faltering growth identified in the community recover with appropriate support

NICE NG75 Key Recommendations

Causes by Mechanism