Developmental Delay

star star star star star
based on 5 ratings

Original Author(s): Dr Louise Ingram and Janie Bamforth
Last updated: 16th April 2022
Revisions: 10

Original Author(s): Dr Louise Ingram and Janie Bamforth
Last updated: 16th April 2022
Revisions: 10

format_list_bulletedContents add remove


Developmental delay is a broad term referring to a delay in any of the four developmental areas. These are:

Global developmental delay refers to a delay in two or more of the above areas simultaneously.

Graphic depicting delays in the developmental domains

Figure 1. Developmental delay in different domains

Risk factors/Causes

Developmental delay has many different causes, including (1):

Table 1: Causes of developmental delay

Category Examples
Neurological Congenital – antenatal vascular event, spina bifida

Acquired: hypoxic ischaemic encephalopathy (HIE), intraventricular haemorrhage, prolonged hypoglycaemia, traumatic brain injury, stroke, epilepsy

Infection Congenital infections – e.g. TORCH infections (toxoplasmosis, rubella, cytomegalovirus/CMV, herpes/HSV)


Meningitis – e.g. meningococcus

Encephalitis – e.g. herpes virus

Neuromuscular disorders Duchenne muscular dystrophy, Spinal muscular atrophy
Genetic disorders Down syndrome
Pervasive developmental disorders Autism
Metabolic disorders Hurle syndrome, Krabbe’s disease, Phenylketonuria
Idiopathic (no obvious cause)
Graphic depicting early development signs of autism, one cause of developmental delay

Figure 2. Graphic depicting early development signs of autism, one cause of developmental delay

Clinical features

Parents might bring a child to see you because:

  • A child is not hitting the expected milestones – in any of the four developmental areas
  • Referred by a Health Visitor as part of regular routine development checks
  • Concerns raised by their early education setting or school
  • Routinely followed-up more closely – for example children born extremely prematurely placing them at higher risk of developmental delay.

There might be concerns in a single area of development such as an 18 month old not yet walking but otherwise hitting milestones, or there might be a more generalised delay, such as a 2 year old who is not walking steadily, only uses one word sentences and is not able to imitate scribbles.

It is important to look for key red flags, such as:

Table 2: Red flags in developmental domains

Developmental domain Red flag
Social Not smiling by 10 weeks
Gross motor Not sitting unsupported by 12 months

Not walking by 18 months

Fine motor Showing hand preference before 12 months of age
Speech and Language Not knowing 2-6 words by 18 months


If any of the above red flags are detected, the child should be referred for paediatric specialist assessment or investigated further. 

Photo of a child with motor delay

Figure 3. Photo of a child with motor delay requiring support to sit after 12 months



The aim of investigations is three-fold. That is to determine:

  • The cause of the delay
  • The likely prognosis
  • Possible treatments.

First-line investigations for global developmental delay are as follows (1):

Table 3: First-line investigations in global developmental delay

Investigation Reason
Full blood count and haematinics Iron deficiency and folate/B12 deficiency can cause developmental delay
Urea and Electrolytes Renal failure and hyponatraemia can cause poor growth
Creatinine kinase Duchenne Muscular Dystrophy
Thyroid function tests Congenital hypothyroidism
Liver function tests Metabolic disorders
Vitamin D Deficiency can cause motor delay
Hearing test Isolated speech and language delay is commonly due to a hearing impairment


Second-line investigations may be helpful as directed by first line investigations or if the cause still unclear. Examples include karyotyping or DNA analysis, more detailed metabolic screens, MRI and EEG.


If any child is suspected to have a developmental delay, they should be referred to a community paediatrician who will perform a detailed developmental assessment, as well as holistic assessment of the child and family. Community paediatricians often use a standardised developmental assessment such as the Griffiths Scales of Child Development or the Schedule of Growing Skills, to assess the child across the developmental domains.

Management is multi-disciplinary and involves referral to specialist therapists to support the child and family. These include speech and language therapists, occupational therapists, portage practitioners and orthoptists. Referral to a hospital paediatrician or specialist might also be indicated. If a reversible underlying cause is found, treatment for this should be instituted.


Only a few causes of developmental delay are reversible, most will result in chronic morbidity with the child requiring specialist support for many years.