Global developmental delay assessment (Assessment of global developmental delay in children)
An assessment for a young child who is slower than expected to reach milestones in two or more areas of development, to understand why and to put the right support in place.
✓ Medically reviewed by a GMC-registered consultant · last reviewed September 2026 · next review September 2027 · how we review
In short
- GDD means significant delay in two or more areas of a young child's development; the assessment works out the pattern, looks for a cause, and guides support.
- Some causes are treatable or important to find (such as hearing or vision problems, thyroid problems, iron deficiency, or genetic conditions), so first tests often look for these.
- A cause is not always found, and the assessment is a snapshot — a young child's development can change, so reassessment over time is normal.
- The most valuable outcome is usually practical: therapies, support at home and nursery/school, and links to the right services — not just a diagnosis.
A plain-English summary. The detail — including risks and recovery — is below.
At a glance
A general guide. Your specialist will give you advice for your situation.
Builds a clear picture of a child's development across all areas and identifies their needs
Routine genetic testing or brain scanning for every child is not appropriate; tests should be guided by the history and examination.
Your child is observed at play and examined while you give a detailed history. The clinician may share initial impressions and explain which tests they...
A clear written summary of the assessment, findings and plan
Your child is observed at play and examined while you give a detailed history. The clinician may share initial...
Hearing and vision checks, blood tests, and any genetic tests or scans are arranged. Some results come quickly...
You are told how your child is developing across areas, whether a cause has been found, and the recommended plan...
Therapies (such as speech and language, physiotherapy or occupational therapy) and support at home and nursery...
What is a global developmental delay assessment?
Global developmental delay (GDD) means a young child is significantly slower than expected to reach their milestones in two or more areas of development — for example movement, speech and language, thinking and learning, social skills, or daily self-care. The term is generally used for children under five.
An assessment looks carefully at how a child is developing across all these areas, mostly by observing the child play and by detailed discussion with parents about pregnancy, birth, milestones, health and family history. The aim is to understand the child's strengths and difficulties, look for any underlying cause, and put the right support in place.
Finding a delay does not always mean finding a single cause. Sometimes investigations identify a specific reason — such as a genetic condition, a hearing or vision problem, a thyroid problem, iron deficiency, or an effect of being born very early. Often, especially at first, no single cause is found, and the focus is on support rather than a label.
It is important to be honest about uncertainty. A young child's development can change, and an early assessment is a careful snapshot, not a fixed prediction. What it reliably does is identify treatable contributors, guide support and therapy, and connect families to help.
Types, options & approaches
There may be different ways to do this. The right approach depends on the clinical question and your circumstances.
Options at a glance
These are the main approaches described in this guide. The right option depends on the diagnosis, your goals and what your clinician thinks is safe.
Developmental history and observation
The core of the assessment: watching the child play and interact, and detailed discussion with parents about milestones, pregnancy, birth, health and family history.
Physical and neurological examination
Checking growth, head size, movement, muscle tone, and looking for any physical features that might point to a cause.
Hearing and vision checks
Often arranged early, because undetected hearing or vision problems can hold back development and are treatable.
First-line tests for treatable causes
Blood and sometimes urine tests to look for reversible contributors such as iron deficiency or an underactive thyroid.
Preparing for your test
- Note your concerns in each area: movement, speech and language, understanding/learning, social skills and daily self-care.
- Write down what your child can and cannot do, and roughly when they reached milestones such as smiling, sitting, walking and first words.
- Bring details of pregnancy and birth (including being born early), serious illnesses, and any hearing or vision concerns.
- Note any family history of developmental delay, learning difficulty, or genetic conditions, including a family tree if possible.
- Bring your child's red book, growth records, and any reports from nursery, health visitor or other professionals.
- Bring a favourite toy or comfort item; the assessment is play-based and your child being relaxed helps.
- Bring a list of any medicines, and note the languages spoken at home.
What happens
Most of the assessment involves observing your child playing and interacting, while a paediatrician or specialist asks detailed questions about pregnancy, birth, early childhood, milestones, health and family history. This builds a picture of your child's development across all areas.
The clinician examines your child — checking growth, head size, movement and muscle tone, and looking for any physical clues to a cause. They will usually arrange hearing and vision checks, and may request first-line blood tests to look for treatable causes such as iron deficiency or an underactive thyroid.
Depending on what they find, they may suggest further tests guided by the examination and family history — for example genetic testing (commonly a microarray and a fragile-X test) and occasionally a brain scan. Many children do not need every test. The clinician then explains the findings, the plan for support and therapy, and any results still to come.
Is this test right for me?
A good consultation should explore whether it's the right choice for you now — including reasons to wait or consider something else.
May not be suitable if…
- Routine genetic testing or brain scanning for every child is not appropriate; tests should be guided by the history and examination.
- A one-off assessment is not a reliable lifelong prediction of a young child's development.
- A developmental assessment is not a substitute for urgent care if a child is acutely unwell or losing skills rapidly.
- A private assessment alone may not provide the ongoing community therapies and school support that most children need, which are largely NHS- and education-based.
Delay or rearrange if…
- An unsettled or unwell child who cannot engage may need the assessment rescheduled.
- Hearing and vision should be checked early, as untreated problems can confound the picture.
- Genetic testing should wait until it has been properly explained and consented, given its family implications.
- Do not delay seeking help if a child is losing skills, having seizures, or is acutely unwell.
Alternatives to discuss
- Developmental surveillance and review over time for milder or uncertain concerns
- Starting therapies and support before, or instead of, extensive investigation
- Hearing and vision assessment as a first step
- Autism assessment where social communication is the main concern
- NHS community paediatric pathway via the GP or health visitor
Before you decide
Use this as a shared-decision checklist. The aim is not just “can this be done?”, but whether it is right for you, now, with the risks and alternatives clearly understood.
What matters most to me?
Think about symptoms, daily life, work, caring responsibilities, sport, fertility, travel, appearance and anxiety — the right choice depends on your priorities, not just the medical facts.
What are all my options?
Ask about waiting, monitoring, medicines, rehabilitation, a smaller or larger procedure, a different test, NHS referral, or a second opinion where that would help.
What would make me pause?
Active infection, pregnancy, unstable medical problems, smoking, medicines that increase bleeding, poor support at home, or feeling pressured are all reasons to slow down and get tailored advice.
What happens if I do nothing today?
For some problems, waiting is safe; for others, delay can make treatment harder. A good consultation should explain the trade-off in plain English.
Benefits
- Builds a clear picture of a child's development across all areas and identifies their needs
- Finds treatable or important contributors such as hearing or vision problems, thyroid problems or iron deficiency
- Can identify a genetic or medical cause, which may guide health care and inform the family
- Connects families to therapies and support, often before any cause is found
- Supports access to the right help at nursery or school
- Gives families a clearer understanding and a plan, reducing uncertainty
Risks & complications
- No single cause being found, which can be frustrating even though support can still go ahead
- Uncertainty about the future, because young children's development can change
- Blood tests being briefly upsetting for a young child
- Needing more than one appointment, or several tests, before a clear picture emerges
- Waiting some time for genetic or specialist test results
- A label being interpreted too rigidly by others rather than as a guide to support
- A scan or genetic test occasionally needing sedation or finding something unexpected (an incidental finding) that needs explanation
- A serious or progressive underlying condition being identified, which needs careful, supported discussion
The biggest sources of uncertainty are that a cause is not always found and that a young child's development can change over time. This is normal and does not mean the assessment has failed — its main value is identifying treatable contributors and guiding support. Ask whether hearing and vision have been checked, which tests are being done and why, and what the plan is for support regardless of whether a cause is found. Genetic testing can have implications for the wider family, so it should be explained carefully before it is done.
Published figures to discuss
It is not meaningful to attach precise percentages to outcomes here, because global developmental delay has many possible causes and a wide range of trajectories. The chance of finding a specific cause, and the likelihood of catching up, depend heavily on the individual child, the pattern of delay and any associated features. Rather than quote misleading figures, the responsible approach is careful assessment, targeted testing and review over time, so we have not stated invented rates.
| Figure | Reported range | How to interpret it | Source / confidence |
|---|---|---|---|
| No single cause found | Common even after assessment | A normal first-line work-up does not mean the delay is not real; support should continue while investigations evolve. | Guide sourcesClinical context |
| Hearing, vision or seizure disorder missed | Recognised | These are important because they can worsen development and may be treatable. | Guide sourcesClinical context |
| Genetic finding of uncertain significance | Recognised with genomic testing | Families may need genetic counselling to understand what a result does and does not explain. | Guide sourcesClinical context |
| Delay to early intervention | Clinically important | Physiotherapy, speech therapy, occupational therapy and educational support should not wait for a perfect diagnostic label. | Guide sourcesClinical context |
These are literature figures, not a personalised prediction. Your own risks and likely benefits depend on your circumstances, your health, and how your care is carried out and followed up.
What happens afterwards
There is no physical recovery from the assessment. 'Afterwards' is about understanding the findings, starting therapies and support, completing any tests, and knowing when development will be reviewed.
- Variation between children in when they reach milestones
- No single cause being found, with the focus on support instead
- Waiting weeks for genetic or specialist results
- Your child making progress with support, sometimes in spurts rather than steadily
- The picture becoming clearer, and sometimes changing, as your child gets older
Aftercare
- Engage with recommended therapies and use suggested strategies at home every day.
- Make sure hearing and vision have been checked and any problems treated.
- Share findings and plans with nursery or school so support is consistent.
- Keep appointments for tests, results and review.
- Look after your child's general health, including iron-rich diet and routine vaccinations.
- Ask about support for the whole family, including practical, emotional and financial help.
- Go back if you have new concerns, if your child loses skills, or if progress stalls.
- A written summary of the assessment and the plan
- Hearing and vision checks completed
- Therapy referrals or appointments arranged
- Nursery or school informed and supported
- A note of which test results are still awaited and when
- Information on family support services
- A named contact and a clear route back for new concerns
⚠ Get urgent help if…
- Your child is losing skills they previously had (for example words, walking or interaction) — seek prompt medical advice
- Your child is not responding to sounds or to their name, or you have concerns about their hearing or vision
- Your child has stiffness, floppiness, persistent unusual movements, or seizures/fits
- Your child is not making any progress, or is falling further behind, despite support
- Your child has poor growth, a head that is growing too fast or too slowly, or is generally unwell
- You have concerns about your child's safety, feeding or swallowing
- For any acutely unwell child with breathing difficulty, a non-fading rash, a fit, or who is very hard to wake, call 999 or go to A&E
Who to contact: your clinician, clinic or test provider first (keep their number to hand). For urgent advice when you can't reach them, call NHS 111. In an emergency, call 999.
General guidance — it doesn't replace the specific advice your specialist gives you.
Results & realistic expectations
A 'good' result is a clear understanding of your child's development across all areas and a practical plan for support — ideally with any treatable contributors found and addressed. Sometimes a specific cause is identified, which can guide health care and inform the family; often no single cause is found, and that does not stop support going ahead.
The assessment cannot reliably predict exactly how a child will develop, because young children change. Its real value is in identifying needs and treatable factors early, and in connecting the family to the right help.
The findings reflect your child at one point in time. Because development continues and can change, especially in the early years, the assessment is reviewed and the plan updated as your child grows. Some children catch up substantially with support; others have longer-term needs. A specific diagnosis, once made, usually remains relevant, but the support plan evolves with the child.
Related tests, treatments or support
A global developmental delay assessment is often combined with hearing and vision checks, speech and language assessment, physiotherapy and occupational therapy input, and sometimes an autism assessment. Genetic testing and, occasionally, a brain scan are arranged where the examination or family history suggests they may help.
Follow-up & long-term care
Follow-up usually involves reviewing development over time, chasing test results, coordinating therapies, and supporting nursery or school. You should be told who is coordinating your child's care (often a community paediatrician), which results are awaited, and how to get back in touch if concerns arise.
- Keep engaging with therapies and using strategies at home over the long term
- Keep hearing, vision and general health under review
- Keep nursery or school informed so support stays consistent
- Attend scheduled developmental reviews
- Seek earlier review if your child loses skills or progress stalls
Repeat, follow-on and what comes next
- A young child's development is reassessed over time and the picture can change, sometimes substantially.
- Investigations may be repeated or extended as new clues emerge or as genetic technology advances.
- A diagnosis may be refined, added to, or occasionally changed as the child grows.
Ask what happens if the result is unclear or needs repeating, and what is included if further tests or follow-up are needed.
What good aftercare looks like
- A clear written summary of the assessment, findings and plan
- Therapies and home/nursery strategies arranged, not just a diagnosis
- Hearing and vision checked and any problems treated
- A named professional (often a community paediatrician) coordinating care
- Defined review points, support for the whole family, and a clear route back for new concerns
What affects the cost
Costs vary a great deal between people and providers, and we don't publish prices. What matters is understanding what drives the cost and making sure your quote is complete. The main things that affect it:
- The length and complexity of the assessment and number of appointments
- Whether hearing, vision and developmental (therapy/psychology) assessments are included
- Which tests are needed, including blood tests, genetic testing and any scans
- Whether a scan requires sedation or a general anaesthetic
- The complexity of any report required for school or an EHC needs assessment
- Whether ongoing therapy and coordination of care are part of the package
- The clinician's fee for the assessment
- Whether a written report is included and how detailed it will be
- The cost of tests such as blood tests, genetic testing and scans, and who reports them
- Whether hearing, vision and therapy assessments are included or charged separately
- What is included if further appointments, therapies or coordination are needed
- What happens, and what it costs, if onward referral or NHS transfer of care is recommended
On the NHS? Assessment and investigation of developmental delay are available on the NHS, usually through community paediatrics, with therapies and support provided alongside; private review is sometimes used for a quicker initial assessment.
You're entitled to your total cost in writing — including reports, follow-up and what happens if the result is inconclusive — before you decide.
Consent traps and marketing red flags
These are not small details. They are often where patients lose choice, time to reflect, or realistic expectations.
Consent traps
- Genetic testing carried out without clearly explaining its possible findings and family implications
- Extensive testing without explaining what each test would change
- Treating an early assessment as a fixed lifelong prediction
- Not checking hearing and vision before drawing conclusions
- Not being clear about who coordinates care and who will see reports
Marketing red flags
- Promises to find 'the cause' or to 'fix' developmental delay through a paid programme
- Routine expensive scans or genetic panels offered to every child regardless of need
- Unproven 'treatments' or supplements claimed to reverse developmental delay
- Discouraging the NHS community paediatric and therapy pathway
- No clear plan for ongoing support, therapy or review after a paid assessment
Choosing a specialist safely
- Check the specialist is on the GMC Specialist Register for this area.
- Make sure they work at a CQC-registered service, and look for membership of the relevant Royal College or professional body.
- You're entitled to time to consider and to have your questions answered before you agree — the specialist who looks after you should explain it, not a salesperson.
- Be wary of pressure: time-limited offers or deposits taken before you've had time to think are red flags, not bargains.
- You're entitled to your total cost in writing — including any follow-up — before you decide.
Questions to ask your medical professional
Take this to your consultation. A good specialist will welcome every one of these.
- Which areas of my child's development are delayed, and what are their strengths?
- Have hearing and vision been checked?
- Which tests are you recommending, and what would each one change?
- If genetic testing is suggested, what could it mean for my child and our family?
- What therapies and support can start now, regardless of whether a cause is found?
- Who will coordinate my child's care, and when will development be reviewed?
- Are you on the GMC Specialist Register for this area, and which Royal College or professional body are you a member of?
- Will you be the specialist who carries out my test, and who looks after me afterwards?
- What are the risks for someone like me, and how often do your own patients have a problem or need it repeated or redone?
- What does a realistic result look like — and what can this test not achieve?
- What are my options, including waiting, doing nothing for now, or choosing a different approach?
- Can I have written information, results and aftercare instructions in a format I can use, including any accessibility or communication support I need?
- What is the total cost in writing, including any follow-ups, and how much time do I have to decide?
Frequently asked questions
What does global developmental delay actually mean?
Will the assessment find a cause?
What tests might my child need?
Could this be autism?
Will my child catch up?
Is this available on the NHS?
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How we made this page
Medically reviewed by a GMC-registered consultant. Written in plain English, checked against NHS, NICE, GMC and relevant Royal College / specialist-society guidance, and kept under review. No clinic paid to appear on this page, and we publish no pricing. This is general information to help you prepare — it is not a substitute for advice from your own clinician. How we review our guides →
Source hierarchy: UK regulator and NHS/NICE guidance first, then relevant Royal College or specialist-society guidance, then peer-reviewed evidence for procedure-specific figures where available.
Sources & standards: NHSGGC — Investigation of early developmental impairment in children Alder Hey Children's Hospital (NHS) — Global Developmental Delay (GDD) NHS Genomics Education — Patient with developmental delay NHS — Signs of autism in children (related developmental concerns)
Reviews reflect patients' experience of care, not clinical outcomes. For procedure volumes and outcome data see PHIN.
Last medically reviewed 2026-09-21. Spotted something wrong or out of date? Report an error in this guide.
Related guides: Childhood developmental assessment · Speech and language concerns in children · Autism assessment (adult) · Children's hearing and balance assessment · Assessing a suddenly unwell or injured child