Children develop at different rates, and there is flexibility in when they achieve milestones. A child who is slow to achieve all milestones or lags behind on a specific developmental domain may have underlying pathology.
Global Developmental Delay
The term global developmental delay applies when a child under 5 years displays delayed development in two or more domains. Often, it is idiopathic (no specific underlying cause is found). Possible underlying causes include:
- Antenatal conditions (e.g., fetal alcohol syndrome and congenital rubella syndrome)
- Perinatal conditions (e.g., prematurity and hypoxic-ischaemic encephalopathy)
- Postnatal conditions (e.g., meningitis and traumatic brain injuries)
- Genetic conditions (e.g., Down’s syndrome and fragile X syndrome)
- Metabolic disorders (e.g., phenylketonuria)
Gross Motor Delay
Key red flags for gross motor delay include:
- Not sitting unsupported by 9 months
- Not walking by 15 months in girls or 18 months in boys
- Abnormal muscle tone (hypertonia with central pathology, hypotonia with central or peripheral pathology)
- Abnormal reflexes (brisk with central pathology, reduced or absent with peripheral pathology)
Causes of a specific delay in the gross motor domain include:
- Cerebral palsy
- Ataxic disorders
- Myopathy (e.g., muscular dystrophy)
- Spina bifida
- Visual impairment affecting balance and co-ordination
Fine Motor Delay
Key red flags for fine motor delay include:
- Not grasping objects by 6 months
- Not transferring objects between hands by 9 months
- Clear hand preference before 18 months
Causes of a specific delay in the fine motor domain include:
- Dyspraxia
- Cerebral palsy
- Muscular dystrophy
- Visual impairment affecting hand-eye coordination
- Congenital ataxia (rare)
Language Delay
Key red flags for speech and language delay include:
- Not babbling by 12 months
- No words by 16 months
- Not combining two-words by 24 months
- Not responding to name or simple commands by 12 months
Causes of a specific delay in the speech and language domain include:
- Environmental factors (e.g., exposure to multiple languages or siblings that do all the talking)
- Hearing impairment
- Learning disability
- Autism
- Cerebral palsy
Management of language delay involves a referral to speech and language, audiology and the health visitor. A safeguarding referral is required if neglect is a concern.
Personal and Social Delay
Key red flags for personal and social delay include:
- Not smiling by 8 weeks
- No interest in people by 6-9 months
- Not pointing or sharing interest by 18 months
- No pretend or imaginative play by 3 years
Causes of a specific delay in the personal and social domain include:
- Autistic spectrum disorder
- Learning disability
- Visual or hearing impairment
- Emotional trauma, attachment disorder or neglect
Last updated October 2025
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