Early Detection Guide
Recognize the early signs of autism in children aged 12-36 months. Evidence-based developmental milestones, red flags by age, and guidance for Ontario parents on when and how to seek assessment.
Direct answer
American Academy of Pediatrics · Hyman et al., Pediatrics 2020 · World Health Organization · Verified 2026-11-03
American Academy of Pediatrics; Hyman et al., Pediatrics 2020; Modified Checklist for Autism in Toddlers (M-CHAT). · Updated 2026-11-03
General information only, not a diagnosis, treatment plan, crisis service, or individual estimate. Confirm your next step with the linked source or a qualified professional.
Clinical research (American Academy of Pediatrics; Hyman et al., Pediatrics 2020) identifies the period from birth to age 6 as the brain’s peak neuroplasticity window. The World Health Organization separately states that timely access to early evidence-based psychosocial interventions can improve autistic children’s ability to communicate and interact socially.
Every month of delayed therapy during this developmental window can have lifelong impacts. Recognizing early signs and seeking assessment promptly gives your child the best chance for optimal development.
Developmental concerns can be discussed with your child's health professional.
Public assessment waits vary by region. Ask your referral team about current local timelines and contact private providers directly for their availability.
Children who receive early intervention show greater gains in language, social skills, and adaptive behavior.
These are warning signs that warrant professional assessment. Having one or more signs does not mean your child has autism, but it does mean you should discuss concerns with your pediatrician.
Warning signs by age
| Age | Warning sign | Source |
|---|---|---|
| 12 Months | No back-and-forth sharing of sounds, smiles, or facial expressions | American Academy of Pediatrics; Hyman et al., Pediatrics 2020 |
| 12 Months | No babbling (ba-ba, da-da, ma-ma) | American Academy of Pediatrics; Hyman et al., Pediatrics 2020 |
| 12 Months | No response to name when called | American Academy of Pediatrics; Hyman et al., Pediatrics 2020 |
| 12 Months | No pointing to show interest or request things | American Academy of Pediatrics; Hyman et al., Pediatrics 2020 |
| 12 Months | No waving goodbye or other gestures | American Academy of Pediatrics; Hyman et al., Pediatrics 2020 |
| 12 Months | Poor eye contact or avoids looking at faces | American Academy of Pediatrics; Hyman et al., Pediatrics 2020 |
| 18 Months | No single words (mama, dada, bottle) | American Academy of Pediatrics; Hyman et al., Pediatrics 2020 |
| 18 Months | No pretend play (feeding doll, talking on toy phone) | American Academy of Pediatrics; Hyman et al., Pediatrics 2020 |
| 18 Months | Does not point to show others something interesting | American Academy of Pediatrics; Hyman et al., Pediatrics 2020 |
| 18 Months | Does not look at objects when you point at them | American Academy of Pediatrics; Hyman et al., Pediatrics 2020 |
| 18 Months | Does not bring toys to show you | American Academy of Pediatrics; Hyman et al., Pediatrics 2020 |
| 18 Months | Loss of any previously acquired skills (regression) | American Academy of Pediatrics; Hyman et al., Pediatrics 2020 |
| 24 Months | No two-word phrases (more juice, go outside, want cookie) | American Academy of Pediatrics; Hyman et al., Pediatrics 2020 |
| 24 Months | Does not follow simple instructions | American Academy of Pediatrics; Hyman et al., Pediatrics 2020 |
| 24 Months | Does not copy actions or words | American Academy of Pediatrics; Hyman et al., Pediatrics 2020 |
| 24 Months | Does not engage in simple turn-taking games | American Academy of Pediatrics; Hyman et al., Pediatrics 2020 |
| 24 Months | Limited interest in other children | American Academy of Pediatrics; Hyman et al., Pediatrics 2020 |
| 24 Months | Repetitive behaviors (hand-flapping, rocking, spinning) | American Academy of Pediatrics; Hyman et al., Pediatrics 2020 |
| 36 Months | Limited speech or difficulty starting conversations | American Academy of Pediatrics; Hyman et al., Pediatrics 2020 |
| 36 Months | Repeats words or phrases exactly (echolalia) | American Academy of Pediatrics; Hyman et al., Pediatrics 2020 |
| 36 Months | Intense interest in specific objects or topics | American Academy of Pediatrics; Hyman et al., Pediatrics 2020 |
| 36 Months | Distress at small changes in routine | American Academy of Pediatrics; Hyman et al., Pediatrics 2020 |
| 36 Months | Sensory sensitivities (covers ears, avoids textures) | American Academy of Pediatrics; Hyman et al., Pediatrics 2020 |
| 36 Months | Difficulty understanding feelings of others | American Academy of Pediatrics; Hyman et al., Pediatrics 2020 |
Regression refers to loss of previously acquired skills. If you notice this, contact your child's health professional.
If your child was using words and stopped, was socially engaged and withdrew, or lost other skills, contact your pediatrician immediately. Regression always warrants prompt assessment.
Track your child’s development across these key domains. The Concern column indicates when you should discuss with your pediatrician.
Age-based milestones and concerns
| Age | Expected Skill | Concern If... | Source |
|---|---|---|---|
| 6-9 mo | Smiles responsively to familiar faces | No social smile | American Academy of Pediatrics; Hyman et al., Pediatrics 2020 |
| 9-12 mo | Uses gestures like reaching or waving | No gestures | American Academy of Pediatrics; Hyman et al., Pediatrics 2020 |
| 12-15 mo | Points to show interest, shares enjoyment | No pointing or sharing | American Academy of Pediatrics; Hyman et al., Pediatrics 2020 |
| 18-24 mo | Engages in simple pretend play | No pretend play | American Academy of Pediatrics; Hyman et al., Pediatrics 2020 |
| 24-36 mo | Plays cooperatively with other children | Plays alone only | American Academy of Pediatrics; Hyman et al., Pediatrics 2020 |
Age-based milestones and concerns
| Age | Expected Skill | Concern If... | Source |
|---|---|---|---|
| 6-9 mo | Babbles with different sounds (ba, da, ma) | Quiet, no babbling | American Academy of Pediatrics; Hyman et al., Pediatrics 2020 |
| 12 mo | Says 1-2 words with meaning | No words | American Academy of Pediatrics; Hyman et al., Pediatrics 2020 |
| 18 mo | Says 10+ words, starts two-word phrases | Fewer than 10 words | American Academy of Pediatrics; Hyman et al., Pediatrics 2020 |
| 24 mo | Uses 50+ words, two-word phrases | No two-word phrases | American Academy of Pediatrics; Hyman et al., Pediatrics 2020 |
| 36 mo | Speaks in sentences, asks questions | Only echoes words | American Academy of Pediatrics; Hyman et al., Pediatrics 2020 |
Age-based milestones and concerns
| Age | Expected Skill | Concern If... | Source |
|---|---|---|---|
| 9-12 mo | Looks at objects when you point | No joint attention | American Academy of Pediatrics; Hyman et al., Pediatrics 2020 |
| 12-18 mo | Imitates actions (waving, clapping) | No imitation | American Academy of Pediatrics; Hyman et al., Pediatrics 2020 |
| 18-24 mo | Follows simple one-step instructions | Does not understand | American Academy of Pediatrics; Hyman et al., Pediatrics 2020 |
| 24-36 mo | Sorts shapes, completes simple puzzles | No interest in toys | American Academy of Pediatrics; Hyman et al., Pediatrics 2020 |
| 24-36 mo | Shows interest in other children | Ignores other children | American Academy of Pediatrics; Hyman et al., Pediatrics 2020 |
The M-CHAT is a standard 20-question screening tool used at 18 and 24 months during well-child visits. It asks about social communication, joint attention, and repetitive behaviors.
Note: A positive M-CHAT screen is not an autism diagnosis. It indicates that follow-up questions or further assessment may be appropriate.
Follow these steps if you are concerned about your child’s development. You are your child’s best advocate — if something feels wrong, pursue answers.
Write down specific behaviors, when you first noticed them, and how often they occur. Include videos if possible. This documentation is valuable for assessments.
Schedule an appointment with your child's doctor. Be specific about your concerns. Request a referral for autism assessment. In Ontario, you can self-refer to some regional centres.
The Modified Checklist for Autism in Toddlers (M-CHAT) is a standard screening tool. Your doctor may use it, or you can complete it online. Positive screening does not mean autism - it means further assessment is needed.
Ask about: (1) a public hospital-based autism assessment clinic, or (2) a regional Children's Treatment Centre. Intake, referral requirements, and capacity vary, so ask the current team what happens next.
If a private route is an option for your family, ask providers for current intake, credentials, assessment scope, report requirements, and a complete written quote. Earlier assessment does not guarantee a particular service or outcome.
Once you receive an autism diagnosis, call Access OAP at 1-833-425-2445 immediately to register.
Ontario says invitations to core clinical services follow OAP registration order. Registration does not promise a funding date.
Central intake for Ontario Autism Program. Call to register after diagnosis.
Provides public autism assessments, early intervention services, and family support.
Parent support, information, and advocacy across all Ontario regions.
Find qualified psychologists for private autism assessment in your area.
Free health advice line to discuss developmental concerns with a nurse.
Community services directory for autism resources and support in your area.
Use our printable milestone tracker to document your child’s development and prepare productive conversations with your pediatrician. Early tracking supports early intervention.
Print this checklist to track your child’s development. Bring to pediatrician appointments to discuss concerns.
Parents know their children best. If you are concerned about development, do not wait. Early assessment leads to earlier intervention, and early intervention leads to better outcomes.
Your child's health
Families navigating autism services in Ontario face a documented multi-year wait. Here is the Ontario data — and a two-minute way to push back, when you are ready.
Guides and tools related to this page.
When should parents seek autism assessment?
Clinical guidelines recommend autism screening at 18 and 24 months during routine check-ups, with referral for full assessment if red flags appear. [AAP] In Ontario, early identification matters critically because every month of diagnostic delay pushes children further from the early intervention window (ages 0-4) that research shows maximizes outcomes.
Source: American Academy of Pediatrics [AAP] · Open source record
Can autistic students get an educational assistant (EA)?
School boards may assign educational assistants (EAs) to autistic students based on needs identified through the IEP process. How EAs are allocated varies by board and school, so ask the principal how support is assigned for your child.
Source: Ontario Ministry of Education — special education · Open source record
What is IPRC and why does it matter?
An Identification, Placement and Review Committee (IPRC) decides whether a student should be identified as exceptional and, if so, recommends a placement. [Education Act; O. Reg. 181/98] A parent may request an IPRC in writing; identification or placement decisions have a school-board appeal process and, in defined circumstances, a further appeal to the Special Education Tribunal.
Source: Ontario Education Act · Open source record
Sources on this page
Key claims are paired with their source, evidence tier, and verification date so readers can inspect the public record directly.
Evidence supports autism screening and intervention commencing in the first 2 years of life — earlier identification directly enables earlier intervention during the highest neural plasticity window
1 in 50
According to the 2019 Canadian Health Survey on Children and Youth, about 1 in 50 children and youth aged 1 to 17 in Canada had an autism diagnosis
WHO recommends accessible, community-based early interventions for children with autism. Timely evidence-based psychosocial interventions improve communication and social engagement
Check the author’s context, review method, and how to report an error.
Founder & Autism Advocate
Lived experience: Parent of autistic child in the OAP system