About This Page
This is a clinician-written, evidence-based summary aligned to the 2026 MLA Content Map. It is intended for medical students and junior doctors preparing for the UKMLA. Always cross-reference with NICE guidance, local protocols, and clinical judgement.
The Bottom Line
- Faltering growth (preferred term): weight falling through 2+ centile spaces on the UK-WHO growth chart, or weight below 2nd centile if previously higher
- Most common cause (>90%): inadequate caloric intake — either insufficient food offered, feeding difficulties, or psychosocial factors (neglect, poverty)
- Organic causes: coeliac disease, cystic fibrosis, cow's milk protein allergy, GORD, UTI, CHD, chronic infections, metabolic disorders
- Non-organic causes: inadequate diet, feeding difficulties, poverty, neglect, maternal depression, disturbed parent-child interaction
- Assessment: detailed feeding and dietary history, growth chart review, developmental assessment, consider safeguarding
- Management: dietetic input, treat underlying cause, monitor growth, consider safeguarding referral if concern
Overview
Failure to thrive (faltering growth) describes inadequate weight gain or weight loss in infancy and early childhood. It is identified by plotting weight, length, and head circumference on appropriate growth charts (UK-WHO charts). A fall through two or more centile spaces, or weight consistently below the 2nd centile when previously higher, warrants investigation. The most common cause is inadequate caloric intake, which may be due to feeding difficulties, insufficient food availability, or psychosocial factors including neglect. Organic causes account for less than 10% of cases but must be excluded.
Epidemiology
Faltering growth is identified in approximately 5% of children under 2 years. It is more common in areas of social deprivation. By definition, ~2% of children will have weight below the 2nd centile at any one time. Risk factors include low birth weight, prematurity, maternal mental health difficulties, social isolation, poverty, and food insecurity. Safeguarding concerns should always be considered.
Clinical Features
Symptoms
Inadequate weight gain or weight loss over time
Feeding difficulties: poor latch, prolonged feeds, food refusal
Vomiting, diarrhoea, or constipation (organic cause)
Recurrent infections
Developmental delay (consequence or associated cause)
Signs
Weight crossing 2+ centile lines downward on growth chart
Wasted appearance: loss of subcutaneous fat, prominent ribs
Length and head circumference may be preserved initially (weight affected first)
Signs of neglect: poor hygiene, inappropriate clothing, nappy rash, withdrawn affect
Signs of underlying disease: abdominal distension (coeliac), clubbing (CF), murmur (CHD)
Investigations
First-line
Growth chart reviewPlot weight, length, and head circumference on UK-WHO charts. Look for centile crossing and pattern
Detailed feeding and dietary historyWhat, how much, how often. Observe a feed if possible. Assess caloric intake vs requirements
Urine dipstick and MC&SUTI can present as faltering growth in infants with no other symptoms
Second-line
BloodsFBC, ferritin, U&Es, TFTs, coeliac screen (anti-tTG), CRP, LFTs. Guided by clinical suspicion
Stool sampleIf diarrhoea: faecal elastase (pancreatic insufficiency), calprotectin (IBD), MC&S
Specialist
Sweat testIf cystic fibrosis suspected
Further investigationsGuided by history and initial results — e.g. echocardiogram (CHD), endoscopy (GI disease), metabolic screen
1
Nutritional management
- Dietetic assessment and input — increase caloric density of feeds
- For breastfed infants: assess latch, frequency, and maternal wellbeing. Support breastfeeding, not replace it
- For formula-fed: ensure correct preparation (concentration), adequate volume
- For older infants: energy-dense foods, frequent small meals, reduce excessive fluid intake (filling without calories)
2
Treat underlying cause
- Coeliac disease: gluten-free diet
- GORD: thickened feeds, positioning, consider PPI or alginate
- CMPA: hypoallergenic formula (extensively hydrolysed or amino acid)
- CHD: may need surgical correction to improve growth
3
Monitor and follow-up
- Regular weight monitoring — weekly initially, then fortnightly
- Plot on growth chart at every contact
- Health visitor involvement for home assessment
- Developmental assessment — catch-up growth often parallels developmental catch-up
4
Safeguarding considerations
- Always consider: is this child being adequately fed and cared for?
- Non-organic faltering growth may be a presentation of neglect
- Assess family circumstances, parental mental health, substance use, domestic violence
- Refer to children's social care if safeguarding concerns
Complications
- Developmental delay: Inadequate nutrition affects brain growth and development
- Immunodeficiency: Malnourished children are more susceptible to infections
- Short stature: If growth faltering is prolonged
- Behavioural difficulties: Food refusal, disordered eating patterns
- Ongoing safeguarding risk: If neglect is the cause
UKMLA Exam Tips
- 1Most common cause is inadequate caloric intake (>90%) — NOT organic disease
- 2Weight is affected FIRST, then length, then head circumference (in that order)
- 3Always consider safeguarding — faltering growth may be a presentation of neglect
- 4UTI can present as faltering growth with no other symptoms — always dip the urine
- 5Coeliac disease should be screened for in any child with unexplained faltering growth
- 6Growth chart interpretation: crossing 2+ centile spaces downward is the key finding
- 7Maternal depression is an important and often overlooked cause of faltering growth
practicetest your knowledge on failure to thriveApply what you've learnt with UKMLA-style questions from the iatroX Q-Bank — paediatrics and beyond.
open q-bank