Signs of Autism in Babies: What Parents Should Watch For by Age

Medically reviewed by the pediatric team at Desert Valley Pediatrics

Key takeaways

• Early signs of autism can show up in a baby’s first year, but they build gradually and look different from one child to the next.
• The clearest signs involve eye contact, social smiles, babbling, response to their name, and gestures like waving and pointing.
• One missed milestone does not mean your baby has autism, but a pattern of them deserves a conversation with your pediatrician.
• The American Academy of Pediatrics (AAP) recommends autism-specific screening at 18 and 24 months, and you can share a concern at any visit before then.

You spend more time with your baby than anyone, so you notice the small things. Maybe your baby rarely looks at you during feeding. Maybe they don’t turn when you call their name. Many parents wonder whether moments like these mean something, and then worry about worrying.

Desert Valley Pediatrics has cared for Las Vegas families for over 25 years, with offices in Summerlin, Centennial Hills, and Southern Hills. Parents ask us about this topic often, and we always welcome the conversation. This guide walks through the signs pediatricians watch for in babies, explains what screening looks like, and tells you what to do next.

Signs of Autism in Babies by Age

Every baby grows at their own pace. Milestones give you a guide, not a deadline. Autism spectrum disorder (ASD) develops gradually, so look for patterns over several weeks instead of judging a single moment.

0 to 3 Months

Signs this early are subtle, and many healthy newborns do some of these things on any given day. Focus on what you see most of the time.

• Fewer expressions. Your baby shows few varied smiles or facial expressions when you talk, sing, or play.
• Little eye contact. Your baby looks away during feeding and holding, or rarely meets your gaze.
• Strong reactions to sensory input. Bright lights or loud noises cause extreme distress, well beyond what you see in other babies their age.

4 to 7 Months

Around this age, babies start trading smiles and sounds with you like a tiny conversation.

• Few social smiles. Your baby rarely smiles back or responds warmly when you smile at them.
• Little back-and-forth sound. Your baby makes few or no coos, gurgles, or other sounds in response to yours.
• Low interest in social play. Games like peek-a-boo get little reaction.
• Later motor milestones. Your baby rolls over or pushes up later than you expect.

8 to 12 Months

Doctors see most of the signs they rely on during this stretch.

• No response to name. Your baby does not turn when you call, and responds less consistently as the months pass instead of more.
• Few or no gestures. Your baby doesn’t wave bye-bye, point at things they want, or reach up to be picked up by 10 to 12 months.
• Little joint attention. Your baby doesn’t follow your gaze or point to show you something interesting.
• Repetitive or unusual movements. You may see hand-flapping, wrist-rotating, stiffened arms and legs, or unusual postures.
• Pulling away from touch. Your baby arches their back or resists cuddling and holding.
• Delayed crawling. Your baby crawls later than you expect.

Signs vs. Diagnosis: What’s Typical and When to Call

Signs are not a diagnosis. No baby shows every sign, and some babies without autism show a few. Only a qualified specialist can diagnose ASD. Your pediatrician looks at the full picture of how your baby grows, plays, and communicates over time.

Call us this week if you notice:

• Your baby loses a skill they used to have, such as babbling or smiling back. Doctors call this regression. Some children develop typically and then lose skills, often between 18 and 24 months.
• No babbling, gestures, or response to name as your baby’s first birthday gets close.
• A worry that keeps coming back, even when you can’t say exactly why.

Mention it at your next visit if you see one sign or a mild difference you want to keep an eye on. You don’t need a perfect list. Describe what you see, and we’ll take it from there.

We may check hearing first. A baby who doesn’t turn at their name may have trouble hearing, and a quick hearing check can rule that out.

Tell us about family history. If your baby has an older brother or sister with autism, let us know. Siblings have a higher chance of ASD, so we follow their development more closely.

Autism Screening and Next Steps

The AAP recommends developmental monitoring at 9, 18, and 30 months, and autism-specific screening at 18 and 24 months. Research shows that by age 2, an experienced professional can often give a reliable diagnosis.

Don’t wait and see. You don’t have to hold your concern until a scheduled screening. If something feels off at 6 months or 11 months, bring it to us then.

What Happens at a Screening Visit

Autism screening at Desert Valley Pediatrics is simple and carries no risk to your child.

1. You fill out a short questionnaire about how your child plays, communicates, and responds to you.
2. Your pediatrician reviews your answers and looks closer at your child’s behavior and development if needed.
3. We refer you to a specialist, such as a developmental pediatrician, psychologist, or neurologist, if your child needs a full evaluation.

Learn more about our autism screening and developmental screening services, which cover children from birth to age 5.

Tools You Can Use at Home

• CDC Milestone Tracker app and Learn the Signs. Act Early checklists. The CDC offers free, parent-friendly milestone checklists in English and Spanish for children as young as 2 months.
• M-CHAT-R questionnaire. This short online questionnaire for toddlers helps you decide whether a professional should take a closer look.
• AAP guidance. HealthyChildren.org explains early signs in plain language.

Try This at Home

A few minutes of play gives you real information. Pick a calm moment when your baby feels rested and fed.

• Call their name from across the room while they play. Notice whether they turn, and whether that happens more often over the weeks.
• Play peek-a-boo, then pause. See whether your baby smiles, makes a sound, or reaches for you to start again.
• Point at a toy and watch whether your baby follows your finger or your gaze.
• Record a short video of anything that concerns you. Showing your pediatrician what you see helps us a great deal.

Bring a checklist to your next visit. Our free one-page checklist lists the signs by age and gives you questions to ask your pediatrician.

When Do Signs Appear, and When Do Doctors Diagnose?

Timing varies widely. Some children show early signs within the first 12 months. Others show signs at 24 months or later. Some gain new skills until around 18 to 24 months, then stop gaining skills or lose the ones they had.

That range explains why we monitor development at every well visit instead of relying on one check. Your well-child visits give us repeated chances to see how your baby grows and to hear what you notice at home.

Beyond the First Year: Toddler Signs to Know

Many signs become easier to spot after your baby turns 1. Watch for:

• Very few words by 16 months
• Very few meaningful two-word phrases by 24 months (not counting repeated words)
• Strong reactions to sounds, smells, tastes, textures, or lights
• Distress at small changes in routine
• Intense interest in particular objects or toys
• Repeating words or phrases, or lining up toys in rows

If you see these signs, ask us about autism screening.

Why Early Support Helps

Young children’s brains stay flexible and keep building new connections. Early intervention takes advantage of that. Studies show that early support improves learning, communication, and social skills in children with ASD, often dramatically.

Nevada also runs an early intervention program for children from birth to age 3. If your pediatrician has a concern, we can explain how referrals work and help you take the first step.

Common Myths

“He’s just shy.” Shyness looks like a baby who warms up slowly to new people. It does not explain a baby who rarely smiles, makes little eye contact, or doesn’t respond to their name.

“Boys talk later.” Some do, but a baby with no babbling or gestures deserves a closer look at any age.

“Let’s wait and see.” Waiting costs you time that early support can use. Ask now, and relax if everything checks out.

Frequently Asked Questions

Can babies show signs of autism?

Yes. Some babies show early signs before their first birthday, such as limited eye contact, few smiles, or no response to their name. Signs vary, and some children show them later.

When do babies start showing signs of autism?

Some babies show signs in their first 12 months. Others show signs after 24 months, and some develop typically for a while before losing skills. Watch milestones as they come and share concerns whenever they come up.

What are the earliest signs of autism in babies?

In the first few months, parents may notice fewer varied expressions, limited eye contact, and strong reactions to lights or sounds. By about 6 months, rarely smiling back and few shared sounds become clearer signs.

Is a lack of eye contact always a sign of autism?

No. Babies look away to rest, and young babies’ vision is still developing. Mention it to your pediatrician when little eye contact continues for weeks and comes with other signs.

Can a baby show some of these signs and be fine?

Yes. Many babies show one or two of these signs and develop typically. Your pediatrician can tell the difference by tracking your baby’s development over time.

When should I ask for autism screening?

Ask whenever you have a concern. Routine autism-specific screening happens at 18 and 24 months, but you never have to wait for it.

We’re Here for Your Family

As pediatricians, we would always rather hear from a parent who has a question than leave a worry unspoken. There’s no such thing as asking too early. Trust your instincts. You know your baby better than anyone.

• Visit us: Our offices in Summerlin, Centennial Hills, and Southern Hills welcome you.
• Message us: Send a note through the Patient Portal.
• Meet us online: Ask whether a telehealth visit fits your question.
• ¿Habla español? Nuestro equipo incluye personal que habla español y está disponible para ayudarle en el idioma con el que se sienta más cómodo.

Ready to talk about your baby’s development? Book an Appointment Online or Call (702) 260-4525

New to DVP? Visit our new patient page. Expecting a newborn? Read our newborn care tips for the first weeks.

Disclaimer: This article is for informational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. The guidance here aligns with general recommendations from the American Academy of Pediatrics (AAP) and the Centers for Disease Control and Prevention (CDC). Always consult your child’s pediatrician with any questions about your child’s development.