Early Signs of Autism in Toddlers: What to Watch For at Every Age

Most early signs of autism in toddlers appear between 12 and 24 months of age. The most reliable markers of an early sign of autism include limited eye contact, no response to a child's own name by 12 months, no pointing or showing objects by 14 months, no two-word phrases by 24 months, and a loss of words, gestures, or social skills the child once had. The American Academy of Pediatrics recommends that every toddler be screened for autism at the 18- and 24-month well-child visits, even when no concern has been raised. This guide walks through every age-specific early sign of autism, what to do as parents the moment a concern surfaces, and how to manage the next steps from first concern to a real support plan.

Why the Early Signs of Autism Matter So Much

Autism is now identified in 1 in 31 children in the United States, according to the Centers for Disease Control and Prevention's 2025 Autism and Developmental Disabilities Monitoring Network report. Toddlers showing an early sign of autism benefit most when intervention begins before age three, the period when the brain's plasticity is highest.

A randomized controlled trial of the Early Start Denver Model, published in the journal Pediatrics, found that toddlers who began intensive early intervention before age two and a half showed significant gains in IQ, language, and adaptive behavior compared with toddlers in community treatment. A more recent narrative review of early intensive behavioral and developmental interventions reported IQ gains of 9 to 15 points in young autistic children who received structured early support.

Recognizing the early signs of autism in toddlers is the first step toward improving communication, independence, and long-term learning trajectories. The longer a toddler waits, the more catch-up support is needed later.

Early Signs of Autism in Toddlers, Age by Age

Toddler development happens in broad windows, but autism-related differences tend to cluster around specific milestones. The CDC's Learn the Signs. Act Early. Program flags these patterns by age. In our sessions, we have seen the same patterns surface again and again.

By 12 Months

• Does not respond to their own name when called
• Does not babble back when spoken to
• Does not use simple gestures such as waving or reaching up to be held
• Avoids or limits eye contact with caregivers
• Shows little interest in peek-a-boo, pat-a-cake, or other social games

By 15 to 18 Months

• Does not point to objects to share interest, known as protodeclarative pointing
• Does not say single words such as "mama" or "dada."
• Does not bring objects to a parent to show or share
• Does not imitate simple actions like clapping or waving goodbye
• Lines up toys or plays with parts of toys, such as spinning wheels, instead of using the whole toy

By 24 Months

• Does not use two-word phrases such as "more juice" or "daddy go."
• Loses words, gestures, or social skills they previously had, a pattern known as developmental regression
• Does not engage in pretend play, such as feeding a doll or pretending to talk on a phone
• Shows strong attachment to routines, with intense distress at small changes
• Repeats specific words or phrases over and over, a pattern called echolalia

By 30 to 36 Months

• Limited interest in playing alongside or with other children
• Difficulty following simple two-step directions like "pick up the ball and bring it here"
• Sensory differences such as covering ears at certain sounds, or unusual focus on lights, textures, or moving objects
• Repetitive body movements such as hand flapping, rocking, or toe walking that persist beyond brief play

Social Communication: The Most Reliable Early Sign of Autism

Social communication differences are the most consistent early sign of autism across the research base. The American Academy of Pediatrics specifically highlights five surveillance markers: not responding to name by 12 months, not pointing to items of interest by 14 months, avoiding eye contact, repetitive movements, and unusual reactions to sensations.

A 2022 study published on PubMed Central compared two parent-report screeners and confirmed that screening at 18 months can flag many toddlers who will later receive an autism diagnosis, with stronger accuracy at 24 months. This is why the AAP recommends screening at both visits, not just one, and why an early sign of autism caught at 18 months is rarely a false alarm worth ignoring.

What to Do as Parents When You Spot an Early Sign of Autism

Spotting an early sign of autism in a toddler is unsettling for any family. The evidence is clear that what to do as parents in the first few weeks shapes outcomes more than almost any later decision. Below is a step-by-step plan that captures what to do as parents the moment a concern surfaces.

1. Document specific observations. Write down what the child does and does not do, with dates. The free CDC Milestone Tracker app makes this easier and shareable with a pediatrician.
2. Take the M-CHAT-R online. The Modified Checklist for Autism in Toddlers, Revised is the AAP-recommended screener for children 16 to 30 months. It takes a few minutes and produces a risk level.
3. Talk to the pediatrician. Bring the notes and screener results to the next well-child visit, or schedule one sooner. Ask directly whether what you are seeing could be an early sign of autism.
4. Request a referral and Early Intervention evaluation in parallel. Under Part C of the Individuals with Disabilities Education Improvement Act (IDEA), every state offers a free Early Intervention program for children under three. A diagnosis is not required to qualify for an evaluation.
5. Skip the "wait and see" advice. Both the CDC and AAP have moved away from passive monitoring. Acting early is consistently associated with earlier identification and better long-term outcomes.

How to Manage Concerns From Screening Through Diagnosis

Knowing how to manage the path from first concern to a formal diagnosis helps families move faster and worry less. How to manage screening and diagnosis depends on the toddler's age and access to specialists, but the path is fairly consistent across states.

A formal autism diagnosis is usually made by a developmental pediatrician, child psychiatrist, child psychologist, or pediatric neurologist using gold-standard tools such as the Autism Diagnostic Observation Schedule, Second Edition (ADOS-2) and the Autism Diagnostic Interview, Revised (ADI-R). Wait times for diagnostic evaluations can stretch from a few months to over a year in some regions. Families benefit from knowing how to manage this gap by starting Early Intervention services right away, since these services do not require a confirmed diagnosis.

In our sessions, families who started early intervention while waiting on a diagnostic appointment consistently report less stress and faster skill gains than families who waited for the appointment first.

A Real-World Pattern: From First Concern to First Skills

Here is a composite example based on a pattern we have seen many times. A 19-month-old toddler stops responding to their name and loses three words used the month before. The parents notice the child no longer points at airplanes overhead. They request a developmental screening at the next pediatric visit. The pediatrician administers the M-CHAT-R/F, which is positive.

The family is referred to a developmental pediatrician with an eight-month wait, and to the state's Early Intervention program, which evaluates the child within three weeks. ABA therapy and speech support begin at 20 months. By 30 months, the child is using two-word phrases and pointing to share interest. A later autism diagnosis at 27 months confirms what the screening flagged, and the head start on intervention is now a documented advantage.

How to Manage Day-to-Day Life While You Wait

Knowing how to manage the day-to-day matters as much as the long-term plan. Practical steps that help most toddlers showing an early sign of autism include keeping a consistent daily routine, narrating activities as they happen ("now we are putting on shoes"), building in short and predictable play sessions, giving extra warning before transitions, and reducing the total number of transitions in the day when possible. These steps support communication, reduce meltdowns, and ease family stress while the formal pathway moves forward. How to manage daily transitions and how to manage sensory load are the two questions families ask most often in this stretch.

Frequently Asked Questions

Sources:

https://learnbehavioral.com/blog/why-early-diagnosis-of-autism-matters-a-deeper-dive

https://www.cdc.gov/act-early/milestones/index.html

https://pmc.ncbi.nlm.nih.gov/articles/PMC8722322/

https://raisingchildren.net.au/autism/learning-about-autism/assessment-diagnosis/autism-signs-in-children-what-to-do

https://www.cdc.gov/autism/treatment/accessing-services.html