Understanding Early Signs
of Autism in Toddlers

A clear, compassionate guide for parents, carers, and educators to recognize early autism signs, developmental milestones, and when to seek professional support.

Early childhood development and autism signs in toddlers

Estimated reading time: 8 minutes

Introduction

Every child develops at their own pace — some talk early, some walk later, and others surprise us in unique ways. But when differences in communication, play, or social interaction seem persistent, parents may wonder if they are noticing early signs of autism.

Autism Spectrum Disorder (ASD) is typically diagnosed after age 2, but early signs can sometimes appear before 18 months. Spotting these signs matters because early intervention can make a profound difference in a child's development.

This article explains the early signs of autism in toddlers, how they relate to ASD levels (1–3), how they differ from GDD (Global Developmental Delay), and how educators use the EYLF (Early Years Learning Framework) to track developmental milestones.

What is Autism in Toddlers?

Autism Spectrum Disorder (ASD) is a neurodevelopmental condition that affects how children perceive, interact, and communicate. While autism is lifelong, its expression varies widely.

In toddlers, autism is often first noticed through differences in:

  • Eye contact.
  • Response to name.
  • Language or gesture use.
  • Play patterns.

Early Signs of Autism

Communication Differences

  • Limited babbling or lack of pointing by 12 months.
  • Few or no words by 18 months.
  • Repetitive phrases rather than new words.

Social Interaction

  • Limited eye contact.
  • Rarely smiling back when smiled at.
  • Prefers to play alone rather than with peers.

Play and Behaviour

  • Lines up toys instead of using them imaginatively.
  • Repetitive movements (hand flapping, rocking).
  • Strong attachment to routines and distress when changed.

Sensory Responses

  • Covers ears to everyday sounds.
  • Fascination with lights, spinning objects, or textures.
  • Strong reactions to certain foods or clothing.

ASD Levels Explained

Autism is described in three levels of support needs:

Level Description
Level 1 Autism: Requires support Toddlers may have mild delays in speech or social play but still show emerging skills.
ASD Level 2: Requires substantial support Noticeable challenges with language, social reciprocity, and flexibility.
Level 3 Autism (ASD Level 3): Requires very substantial support Marked absence of speech, little interest in peers, and reliance on strict routines.

These levels of autism do not predict a child's future but help guide the right level of support.

Autism vs GDD (Global Developmental Delay)

GDD is diagnosed when children under 5 show significant delays in two or more developmental areas (language, motor, cognition, social).

Key Differences

  • Autism: Social and communication differences are central.
  • GDD: Broader, generalised delays.

A toddler with GDD may later receive an ASD diagnosis, but not always. Differentiating between the two often requires time and professional observation.

Developmental Milestones and the EYLF

The Early Years Learning Framework (EYLF) guides Australian educators in supporting children's learning from birth to age 5. For toddlers, key milestones include:

  • Communication: Using words, gestures, and early sentences.
  • Social Development: Playing alongside or with peers, turn-taking.
  • Cognitive Development: Imitation, problem-solving, attention span.
  • Physical Development: Walking, climbing, fine motor skills like stacking blocks.

Tracking developmental milestones (EYLF) helps professionals identify whether differences may reflect autism, GDD, or simply individual variation.

Diagnosing Autism in Toddlers

Diagnosis usually involves:

  • Developmental history (from parents and caregivers).
  • Observation of behaviour and interaction.
  • Screening tools such as M-CHAT (Modified Checklist for Autism in Toddlers).
  • Referral to a paediatrician, psychologist, or speech pathologist.

Early assessment is key because targeted support (speech therapy, occupational therapy, parent training) can strengthen outcomes.

Find Early Childhood Development Specialists

Connect with qualified professionals who specialize in early autism assessment and intervention for toddlers.

Search for Autism Specialists

FAQs About Early Autism Signs

Yes, some signs appear before 18 months, though most formal diagnoses occur around age 2–3.

Not always. Some toddlers are late talkers without ASD, but combined with other behaviours, it may be significant.

Yes. Support needs may shift with therapy, development, and environment.

Autism is defined by differences in communication and behaviour, while GDD refers to broad developmental delays.

Not always — but if it's persistent alongside other signs, consider professional evaluation.

References & Further Reading

  1. American Psychiatric Association. (2013). DSM-5: Autism Spectrum Disorder. (link)
  2. Australian Government Department of Education – EYLF Guidelines. (link)
  3. Autism Awareness Australia – (link)
  4. Centers for Disease Control and Prevention – Signs and Symptoms of Autism Spectrum Disorder. (link)

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Disclaimer: This article is for educational purposes only and is not a substitute for professional medical advice. Always consult a qualified health professional for diagnosis and support.