Normal Child Development
Normal child development follows predictable milestones across four domains: gross motor, fine motor/vision, speech/language/hearing, and social/behaviour. Knowledge of milestones is essential for identifying developmental delay.
Key Facts
Four developmental domains: Gross motor, fine motor/vision, speech/language/hearing, social/behaviour/play Key milestones: Sitting unsupported (6-8 months), walking (12-18 months), first words (12 months), 2-word phrases (18-24 months), scribbling (15 months), tower of 6 cubes (2 years) Primitive reflexes: Moro (disappears 4-6 months), grasp (3-4 months), rooting (3-4 months), ATNR (6 months) — persistence suggests neurological abnormality Social smile: 6 weeks — one of the earliest and most important milestones Stranger anxiety: 7-9 months — indicates normal attachment and cognitive development Limit ages: Age by which milestone should be achieved (e.g., not sitting by 9 months, not walking by 18 months — warrants assessment) Red Book: Personal Child Health Record — UK parents carry this for recording immunisations, growth, and developmental checks Development follows a cephalocaudal (head to toe) and proximodistal (centre to periphery) pattern
Overview
Key Facts
Understanding normal developmental milestones is fundamental to paediatric practice. Assessment of development is part of every child health surveillance encounter and is essential for early identification of developmental delay or disorder.
Epidemiology
Developmental delay of any kind affects approximately 5-10% of children. Global developmental delay (delay in ≥2 domains) affects approximately 1-3%. Early identification through the Healthy Child Programme and GP/health visitor reviews improves outcomes through early intervention.
Aetiology
Normal development is influenced by:
- Genetic factors: Intelligence, temperament, physical characteristics
- Environmental factors: Nutrition, stimulation, attachment, socioeconomic status
- Prenatal factors: Maternal health, substance exposure, infections
- Perinatal factors: Prematurity, birth asphyxia, neonatal illness
Pathophysiology
Development reflects progressive myelination and synaptogenesis in the CNS. Myelination proceeds in a predictable sequence (brainstem → cerebellum → cortex), explaining the cephalocaudal pattern of motor development. Critical periods exist for certain functions (e.g., visual development, language acquisition), during which the brain is most receptive to environmental input.
Clinical Presentation
Gross Motor Milestones
| Age | Milestone |
|---|---|
| Newborn | Limb flexion, head lag on pull to sit |
| 3 months | Head control in prone (lifts head 45°) |
| 6 months | Sits with support; rolls over |
| 7-8 months | Sits unsupported |
| 9-10 months | Crawling; pulls to stand |
| 12 months | Walks with one hand held; cruising |
| 15 months | Walks independently |
| 2 years | Runs; kicks ball |
| 3 years | Pedals tricycle; climbs stairs alternating feet |
Fine Motor/Vision Milestones
| Age | Milestone |
|---|---|
| Newborn | Follows face to midline |
| 3 months | Follows past midline; hand regard |
| 6 months | Palmar grasp; reaches for objects |
| 9 months | Index finger approach; transfers hand to hand |
| 12 months | Pincer grip; bangs two cubes together |
| 15 months | Tower of 2 cubes; scribbles |
| 2 years | Tower of 6 cubes; circular scribble |
| 3 years | Tower of 9 cubes; copies circle |
Speech/Language Milestones
| Age | Milestone |
|---|---|
| 6 weeks | Social smile |
| 3-4 months | Laughs; coos |
| 7 months | Babbles ('bababa', 'mamama') |
| 12 months | 2-3 words with meaning; understands 'no' |
| 18 months | 10-20 words; points to objects |
| 2 years | 2-word phrases ('mummy go'); 50+ words |
| 3 years | 3-word sentences; talks constantly; asks 'why?' |
| 4 years | Fluent speech; tells stories |
Red Flags
- No social smile by 8 weeks
- Not sitting by 9 months
- Not walking by 18 months
- No words by 18 months
- No 2-word phrases by 2 years
- Loss of previously acquired skills (regression) — urgent investigation
Differential Diagnosis
| Domain Delayed | Possible Cause | Investigation |
|---|---|---|
| Global delay (≥2 domains) | Genetic (Down's, fragile X), cerebral palsy, metabolic | Genetics, MRI, metabolic screen |
| Isolated motor delay | Cerebral palsy, myopathy, spinal muscular atrophy | MRI, CK, nerve conduction |
| Isolated speech delay | Hearing loss, autism, environmental deprivation | Hearing test, ADOS-2, developmental assessment |
| Regression | Neurodegenerative disorder, metabolic, epileptic encephalopathy | Metabolic screen, MRI, EEG |
Diagnosis / Investigation
Bedside
- Developmental history: Milestones in all four domains; parental concerns
- Developmental assessment: Observation of play, movement, communication
- Growth: Weight, length/height, head circumference plotted on centile charts (UK-WHO)
Bloods
- Not routine for normal development assessment
- If delay identified: TFTs, FBC, ferritin, lead level, metabolic screen, genetic testing
Imaging
- MRI brain: If motor delay, regression, or abnormal neurology
Special Tests
- Hearing test: Newborn hearing screening (AABR/OAE); distraction test (7-9 months); pure-tone audiometry (>3.5 years)
- Vision screening: Red reflex (newborn); orthoptist screening (4-5 years)
- Standardised developmental assessment tools: Bayley Scales, Griffiths, Schedule of Growing Skills
Management
Non-pharmacological
- Health visitor developmental reviews: Part of UK Healthy Child Programme (HCP) at 9-12 months, 2-2.5 years
- GP 6-8 week check: Includes developmental assessment
- Early years support: Portage (home-based early education), speech and language therapy, physiotherapy, occupational therapy
- Parental education: Encourage play, reading, interaction
Pharmacological
- No medications for normal developmental variation
- Specific conditions identified during assessment may require treatment (e.g., hypothyroidism, epilepsy)
Referral Criteria
- Parental concern about development — take seriously; refer for assessment
- Not meeting limit age milestones — community paediatrician
- Regression — urgent paediatric neurology
- Suspected autism — NICE CG128 pathway
- Suspected hearing loss — audiology
- Suspected visual impairment — ophthalmology
Prognosis
- Normal variation: Many children develop at slightly different rates within the normal range
- Premature children: Use corrected age until 2 years when assessing milestones
- Early intervention: Improves outcomes across all types of developmental delay
- Language delay: ~50% of late talkers (18-month no words) catch up by age 3; persistent delay may indicate autism or language disorder
- Motor delay: Isolated motor delay with normal other domains often has good prognosis (benign motor delay); cerebral palsy requires lifelong support
Other Relevant Information
UK Healthy Child Programme — Key Developmental Reviews
| Age | Review Content |
|---|---|
| Newborn | Physical examination, hearing screen |
| 6-8 weeks | GP check, growth, development, maternal wellbeing |
| 9-12 months | Health visitor review, growth, development |
| 2-2.5 years | Health visitor review, language assessment (ASQ-3) |
| 4-5 years | School entry — vision, hearing, growth |
Primitive Reflexes
| Reflex | Appears | Disappears |
|---|---|---|
| Moro | Birth | 4-6 months |
| Palmar grasp | Birth | 3-4 months |
| Rooting | Birth | 3-4 months |
| ATNR | Birth | 6 months |
| Stepping | Birth | 2 months |
| Parachute | 6-9 months | Persists |