The short answer
A developmental assessment checks how your baby is learning, moving and communicating. In England, the 9–12-month review often includes an ASQ-3 questionnaire; this is not a diagnosis or the same timetable as US screening.
In this guide · 12 sections
Keep in mind
- When a clinician asks about how your baby moves and communicates, that is part of developmental monitoring. Screening goes further: it uses age-appropriate, research-tested questionnaires or other standardised tools to assess several areas.
- Depending on the tool, screening can cover movement, hand skills, communication, problem-solving and social-emotional behaviour. Progress in one area does not mean every area moves at the same pace.
- CDC describes milestones as behaviours that at least about 75% of children show by a given age. Missing one item does not by itself establish a developmental disorder.
- Contact a healthcare professional without waiting for a scheduled review if your baby clearly loses a skill, seems less responsive to sound or communication, or uses one side much less.
What exactly is developmental screening?
When a clinician asks about how your baby moves and communicates, that is part of developmental monitoring. Screening goes further: it uses age-appropriate, research-tested questionnaires or other standardised tools to assess several areas.
The goal is not to attach a label to your baby but to identify whether a more detailed assessment might help. Two babies with different answers do not necessarily have the same needs.
Why is nine months an important time?
Around nine months, babies may show many changes in sitting balance, hand movements, sounds and responses to familiar people. It is a helpful point to discuss these areas together.
The AAP recommends general screening at 9, 18 and 30 months in the US. In England, a health visitor normally offers a 9–12-month review, often using the ASQ-3 questionnaire. The two systems should not be treated as identical.
Are monitoring and screening the same?
Monitoring means noticing what your baby does in everyday life over time: looking when you say their name, searching for a toy or using both hands.
Standardized screening is a separate process with defined questions and scoring. CDC milestone checklists help families observe development but do not replace validated screening tools.
Which developmental areas are considered?
Depending on the tool, screening can cover movement, hand skills, communication, problem-solving and social-emotional behaviour. Progress in one area does not mean every area moves at the same pace.
CDC’s nine-month milestones include sitting without support, varied babbling, responding to one’s name, looking for a dropped object and banging two objects together. These examples are not identical to a screening questionnaire and do not diagnose anything.
How should milestone checklists be interpreted?
CDC describes milestones as behaviours that at least about 75% of children show by a given age. Missing one item does not by itself establish a developmental disorder.
Think about the situation in which a skill appears. Talk with your clinician if a skill has disappeared or several areas concern you; do not turn a home checklist score into a diagnosis.
What happens during a screening?
In England, the health visiting team may ask you to complete an ASQ-3 questionnaire before the 9–12-month review. Your baby may also be observed and you can ask for help completing it.
Being tired or wary of a new setting can affect what a baby shows that day. Your observations at home, short videos and questions help provide context.
Does an at-risk result mean a diagnosis?
No. A screening result suggesting further evaluation is not proof of a condition. A clinician may recommend a fuller developmental assessment, hearing checks or appropriate specialist support.
Likewise, a result within the expected range does not guarantee that no future concern will emerge. Developmental monitoring and communication continue after screening.
What can you do today?
Note a few everyday examples and roughly when you noticed them: responding to their name, searching for a toy, making sounds or moving on the floor. There is no need to turn daily life into an exam.
Bring concrete questions such as “My baby usually looks when I say their name, but I have a question about their sounds.” If your baby was premature, ask about the use of corrected age.
When should you seek advice sooner?
Contact a healthcare professional without waiting for a scheduled review if your baby clearly loses a skill, seems less responsive to sound or communication, or uses one side much less.
You do not need a definite symptom list to ask a question. Seeking advice or requesting screening does not mean you have diagnosed your baby.
When to seek support
Some signs need emergency help; other concerns can be discussed with your child’s healthcare team.
- Contact a healthcare professional without waiting for a scheduled review if your baby clearly loses a skill, seems less responsive to sound or communication, or uses one side much less.
- You do not need a definite symptom list to ask a question. Seeking advice or requesting screening does not mean you have diagnosed your baby.
Sources used for this guide
- American Academy of Pediatrics / HealthyChildren.org — American Academy of Pediatrics / HealthyChildren.org
- American Academy of Pediatrics / HealthyChildren.org — HealthyChildren – Checkup Checklist: 9 Months Old
- CDC — Milestones by 9 Months
- Centers for Disease Control and Prevention (CDC) — 9 Month Online Milestone Checklist
- Centers for Disease Control and Prevention (CDC) — CDC – Developmental Monitoring and Screening – 16 Şubat 2026
- Centers for Disease Control and Prevention (CDC) — Key Points about CDC Developmental Milestone Checklists
- Centers for Disease Control and Prevention (CDC) — Concerned About Your Child’s Development?
English editorial review:
The English text and regional guidance have been checked editorially. This is not an individual clinical assessment.
Luluna provides general parenting information. It does not diagnose conditions or replace your child’s healthcare professional.
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