Many parents expect clear-cut signs when it comes to diagnosing autism in young children. However, autism doesn’t always present itself in obvious ways. Subtle delays or deviations in developmental milestones can be early indicators of Autism Spectrum Disorder (ASD), especially during the critical first three years of life. Unfortunately, these signs are often overlooked or misattributed to temperament, personality, or delayed development. Discover subtle autism signals in child development and learn how early action can lead to stronger outcomes through timely intervention.

At Momentum Behavioral Care, we believe that early identification and intervention are key to supporting each child’s unique development. This blog will help you understand what milestones to watch for, identify common red flags that often go unnoticed, and know when to take the next step.

Understanding Key Developmental Milestones

Children reach developmental milestones in a sequence that typically includes gross motor, fine motor, communication, cognitive, and social-emotional skills. While every child develops at their own pace, consistent and significant delays can be early indicators of ASD.

• Gross Motor Milestones: Sitting, crawling, standing, and Most children begin to walk independently by 15 months.
• Language and Communication: Babbling by 6 months, saying simple words by 12–15 months, and forming 2-word phrases by 24 months.
• Cognitive Skills: Problem-solving, object permanence, and the ability to follow simple
• Social-Emotional Development: Making eye contact, engaging in back-and-forth play, showing interest in peers, and expressing basic emotions.

Delays or unusual development in any of these domains—especially when they occur together—may warrant further observation and evaluation.

Red Flags That Often Get Overlooked

Some early signs of autism are subtle and easily attributed to non-clinical factors. However, research shows that these behaviors, when persistent, may be meaningful:

• Lack of back-and-forth babbling: By 9 months, most infants engage in cooing and babbling during social interaction. A lack of this early vocal play may indicate a communication delay.
• Delayed pointing or gesturing: Children typically begin pointing to indicate interest by 12–15 months. The absence of this behavior can signal social communication challenges.
• Limited imitation of expressions or sounds: Infants often mimic facial expressions or sounds. A lack of imitation may suggest difficulty with social reciprocity.
• Minimal interest in peers or pretend play: By age 2, most children show interest in peers or engage in simple pretend scenarios (e.g., feeding a doll). Children with autism may prefer objects or routines over social play.
• Unusual attachment to objects or routines: Atypical fixation on spinning objects, lining up toys, or intense distress over routine changes may reflect restricted, repetitive behaviors.

Clinical Insight: According to a study in the Journal of Autism and Developmental Disorders (Zwaigenbaum et al., 2015), these early behaviors can predict later autism diagnoses with high sensitivity—especially when combined.

Real-Life Scenarios: When Signs Were Missed

Case 1: A 2-year-old named Ella did not engage in pretend play or respond to her name. Her parents thought she was “just independent” and appreciated quiet activities. It wasn’t until preschool teachers noted social withdrawal that a referral was made. Diagnosis: Autism Level 1.

Case 2: Lucas, a bilingual child, had limited speech by age 3. His language delays were initially attributed to dual language exposure. However, he also showed little joint attention and preferred solitary play. Diagnosis was followed after a developmental screening confirmed multiple red flags.

These stories are not uncommon—and they highlight how well-meaning reassurances can lead to delayed intervention.

When to Seek an Evaluation

If you’re noticing delays or atypical behaviors, trust your instincts. Here are the steps to take:

• Use Screening Tools: The M-CHAT-R/F (Modified Checklist for Autism in Toddlers) is a validated screening tool for children aged 16–30 months.
• Document Behaviors: Keep a journal of your child’s developmental progress and concerning behaviors.
• Talk to Your Pediatrician: Share your observations and ask for a referral to a developmental pediatrician or psychologist if concerns persist.
• Push for Action: If you’re told to “wait and see,” but you feel something is wrong, seek a second opinion.

Why Early Action Matters

Starting intervention as early as possible can make a significant difference. According to research in the Journal of Applied Behavior Analysis (Smith, 2012), early ABA therapy has been linked to improvements in language, social engagement, and adaptive skills.

Brain plasticity is greatest during the first five years of life. Children who receive early intervention are more likely to develop functional communication, reduce challenging behaviors, and succeed in mainstream educational settings.

Momentum Behavioral Care’s Role in Early Intervention

At Momentum Behavioral Care, we provide:

• Free developmental screenings to assess early concerns.
• Family consultations to explain signs, next steps, and therapy options.
• Referral assistance to connect families with licensed diagnostic professionals.
• Personalized ABA therapy tailored to your child’s specific strengths and needs. Our team is here to support you from the first concern to lasting progress.

Subtle Doesn’t Mean Insignificant

Missing milestones doesn’t always mean something is wrong—but ignoring them could delay the support your child needs. The earlier you identify developmental differences, the more opportunities your child will have to grow and thrive.

Don’t wait for certainty to take action—start with a conversation.

Reach out or refer your child at momentumbehaviorcare.com.