Signs of Autism in Infants : Spot the Early Red Flags

Signs of autism in infants can include limited eye contact, differences in early communication, less interest in social interaction, repetitive movements and strong reactions to sounds or textures. Some signs of autism in babies may appear before their first birthday. Autistic infants might smile at others less often, respond less when spoken to, or reach motor milestones like sitting or crawling later.

Some may rock, flap their hands, show autism tics, or show subtle facial characteristics of autism, such as different facial expressions or fewer social smiles. One or two of these behaviors don’t always mean autism, but if you notice several signs, talking to your GP or pediatrician early means you can get support at the time it helps most.

Early Signs of Autism in Infants: What to Look For

Recognizing the early signs of autism in infants helps families get support early. Every child develops at their own pace, but certain behaviors and differences may point to autism spectrum disorder (ASD). Below are key signs, grouped by age, to help parents notice possible concerns early.

Signs of Autism in Babies 2 Months Old

At 2 months, most babies start smiling, cooing and responding to voices and faces. Autism is not diagnosed this early, but some subtle signs may appear, including:

• Limited eye contact: the baby may rarely look at faces or follow objects with their eyes.
• Reduced social response: they may not respond to familiar voices or smile back as often.
• Different body movements: some babies may flap their hands, stiffen or make repetitive movements.
• Lots of crying or unusual quietness: the baby may cry more than usual or seem unusually still and passive.

Remember that every baby develops differently, and noticing one or two of these behaviors doesn’t necessarily mean autism.

Signs of Autism in Babies 6 Months Old

1. Limited or no eye contact
2. Fewer joyful expressions, such as big smiles
3. Less response to social engagement (for example, not looking at familiar faces)
4. Less interest in familiar voices or sounds
5. Less interest in watching people’s faces or movements
6. Unusual quietness or fewer sounds (vocalizations)

Signs of Autism in Babies 9 Months Old

1. Few or no back-and-forth gestures, like reaching, waving or pointing
2. Limited or no response to their name
3. Unusual reactions to sounds, such as being very sensitive or seeming not to notice

Signs of Autism in Babies 12 Months Old

1. No babbling or very few sounds
2. Few gestures like pointing or waving
3. Avoiding some kinds of physical affection (for example, resisting being held or cuddled), often because of sensory sensitivity

Signs of Autism in Newborns

Parents often ask about signs of autism in newborns, or autism symptoms in newborn babies. The honest answer is that autism can’t be reliably seen at birth or in the first few weeks. Newborns spend most of their time sleeping, feeding and crying, and the social skills that autism affects haven’t developed yet.

Research on younger siblings of autistic children has found that some differences, such as in how babies look at faces, may show up in the first months of life, but these differences are subtle and only show up in research settings, not in everyday life. So if your newborn is unsettled, feeds poorly or avoids eye contact in the first weeks, it isn’t a sign of autism on its own. Talk to your GP or child health nurse about any worries, and keep an eye on development over the following months.

If you already have an autistic child, a younger sibling has a higher chance of being autistic too. It’s worth letting your GP or pediatrician know so they can keep a closer watch on development.

Signs of Autism in Infants: 5 Key Areas

Signs of Autism in Infants

Signs of autism in infants usually aren’t obvious at birth but develop over time. As babies grow, they may reach milestones at different times or show different social behaviors.

The signs listed here aren’t the only indicators of autism. This list highlights some behaviors that, along with other signs, might suggest a need for further assessment. Many autism symptoms in infants are a baby’s way of protecting themselves from overwhelm, not problems in themselves.

1. Absence of Vocalizations

A baby who makes very few sounds is sometimes described as “passive” or a very “easy” baby. For many babies this is just their temperament, but a baby who rarely cries, babbles or seems interested in their surroundings could be showing a sign of autism.

Few vocalizations can sometimes mean language develops later or differently. It may take until around 2 years of age to know for sure, and many children who are slow to talk go on to use speech, while others communicate well with signs, pictures or devices.

2. Heightened Sensory Sensitivities

Heightened sensory sensitivities and repetitive movements (sometimes called stereotypic behavior, or “stimming”) may be a sign of autism in infants. However, research suggests that repetitive movements at this age don’t necessarily mean a child is autistic.

Repetitive movements in infancy can have many causes, including other developmental differences such as intellectual disability, and many babies who are not autistic do them too. Some autistic children don’t show repetitive movements as infants and develop them later as a way to self-regulate and meet their sensory needs.

Heightened sensory sensitivity may look like strong reactions to sound and touch (hyper-responsiveness). As the child grows, sensory differences can also show up as hypo-responsiveness, which may look like not noticing loud noises, paying little attention to new objects, or seeming to have a high pain tolerance. Some infants may also show autism tics as part of their self-regulation responses.

3. Differences in Joint Attention

Joint attention in infants is the ability to share attention (look and be present) with another person, for example looking at the same toy, or responding when someone tries to interact. Signs of later-developing joint attention in an infant may include not following objects with their eyes, not looking when an adult points at something, or finding it hard to stay interested in a shared activity or object.

4. Differences in Social Responsiveness

Differences in social responsiveness mean a baby responds to the social cues of the people close to them less often, or in different ways. This can leave both parent and baby feeling out of sync, and parents can feel confused about why their baby isn’t responding the way they expected.

It can affect communication and how parent and child read each other’s emotions. Many parents describe feeling rejected or worried, and those feelings are completely understandable. It helps to know that a baby who looks away or doesn’t smile back isn’t rejecting you. They may simply be finding the social and sensory input overwhelming, or connecting in a different way.

Differences in social responsiveness may show up when a baby makes limited eye contact, copies others less, doesn’t respond to their name, uses fewer facial expressions, doesn’t return a social smile, or seems less interested in the people around them.

5. Delayed Motor Development

Fine and gross motor skills are hard to assess in infants, but research shows that differences in these skills become clearer from around 6 months of age. From 6 months, some autistic infants begin to make repetitive or fidgety movements.

This sign is hard to judge at this age, but along with other signs it can help decide whether further assessment is a good idea.

📌 MUST READ :
Signs of Autism in 1 Year Old
Signs of Autism in 2 Year Old

Parenting Challenges in Infants with Autism

Seeing symptoms of autism in your baby can be confusing and upsetting. Many parents naturally follow their baby’s lead, giving space when the baby seems to want less interaction, out of respect for who they are and what they prefer.

Respecting your baby’s comfort is important. At the same time, babies learn to communicate through lots of gentle, back-and-forth moments with the people who love them. The goal is to find ways of connecting that suit your baby, not to push interaction they find overwhelming, and not to step back altogether.

What to Do If You Notice Signs of Autism in Your Baby

• Write down what you notice. Note the behaviors, when they happen and your baby’s age. Short videos on your phone are very helpful for health professionals.
• Talk to your GP or child health nurse. In Australia, your baby’s routine health checks (and the milestones in your baby’s health record book) are a good time to raise concerns. You don’t need to wait for the next check.
• Connect on your baby’s terms. Get down to their level, copy their sounds and movements, and join in with what interests them. Short, joyful moments of connection add up.
• Watch the sensory load. If your baby seems overwhelmed, try a quieter room, softer lighting, fewer toys or a calmer voice.
• Talk and narrate. Describe what you’re doing and what your baby is looking at, with lots of pauses so they have a chance to respond in their own way.
• Look after yourself. Worry is exhausting. Lean on family, friends or parent support services while you wait for answers.

What Causes Autism in Babies?

There is no single cause of autism in babies. Research shows genetics play the biggest part, which is why autism often runs in families. Some factors before birth, such as being born very early or having older parents, are linked with a higher chance. Autism is not caused by vaccines, by anything a parent did or didn’t do, or by how a baby is cared for. A baby is autistic from the start; the signs simply become easier to see as they grow.

How to Handle the Challenges of Getting an Autism Diagnosis

Getting an autism diagnosis can take time and be stressful for parents, who are often worried while watching their child’s development. Usually, the first step is to raise your concerns with your GP.

After this first appointment, the GP may refer your child to a pediatrician or child psychiatrist, after ruling out other possible medical causes, such as hearing problems.

While you wait for an assessment, it’s a good idea to look for support services to learn more about autism and strategies to support your child’s development. You don’t need a diagnosis to start supporting your child at home.

How is Autism Treated In Children?

3 Early Intervention Therapies

Autism is a lifelong difference, and early support can make a big difference to your child’s communication, wellbeing and confidence. Early support may include autism speech therapy, occupational therapy and developmental or behavioral support.

Children can start these supports even before they have a diagnosis, and starting early often helps most. A team of professionals works together to support children to communicate, connect with others and understand and manage big feelings. Each child should have a plan that fits their needs and builds on their strengths. Early support also gives parents the chance to work with doctors and therapists, and to learn strategies they can use every day at home.

How to Diagnose Autism in Children?

Most children in Australia are diagnosed with autism around the age of 3 or 4, although autism can often be reliably diagnosed from around 2 years of age, and signs can sometimes be seen earlier.

A diagnosis is made when a child shows ongoing differences in two areas: social communication and interaction, and restricted or repetitive behaviors, interests or sensory responses. Some of these areas are hard to assess in infants, but adapted assessments can still identify signs early and what they might mean for the child.

FAQs: Signs of Autism in Infants

Conclusion

Recognizing the early signs of autism in infants means families can get support early, which benefits both the child and the whole family. Knowing about later stages, such as signs of autism in teens, helps families plan for ongoing support. If you notice behaviors that worry you, talk to a health professional.

For more resources and expert advice, visit Autism360

Kyran Ewing

I am a dedicated educator turned Board Certified Behavior Analyst with a deep passion for helping neurodivergent children and their families achieve positive and lasting behaviour change.
My background in teaching has given me a strong foundation in understanding the unique needs of neurodivergent learners. Now, as a BCBA, I am thrilled to be working with Autism 360, where I am committed to providing invaluable support to families within the autistic community, both locally and afar.