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Click here for PDF: Autism Spectrum Disorder Warning Signs Checklist

Parents frequently ask if there is a way to detect spectrum issues early on. We saw symptoms in my son which suggested problems as early as 4 months old. It is now clear babies show symptoms which can be early warning signs for autism.

In and of themselves, these symptoms are sometimes just that – a single incident or issue with no further indications. However, historically, it is easy to notice symptoms children on the spectrum had in common during infancy and early childhood.

It is also available for download on the site Please share with friends or family who are having a baby or have small children. Any one symptom is usually not of concern but a combination of symptoms, repeated frequently, can be an early warning sign.

“Normal” is extremely varied. These are general guidelines to consider as your child develops. In and of themselves, many of these characteristics or traits are part of normal development. The warning signs build by developmental stages but can appear at any age. Please note this is solely a suggestive list – it is not to be construed as medical or expert advice.

If your child exhibits several warning signs, please talk to your pediatrician or a child development expert specializing in autistic spectrum disorder.

If your child shows several warning signs or does not have mostly checked boxes under the blue headings (things your baby should be doing), do not let your doctor put you off. The earlier your child receives intervention, the better the outcome. I have tried to make this list as inclusive as possible.

Age: 2 Months
Things your baby should be doing:

  • Follow you with his/her eyes
  • Startle at loud noises
  • Gaining weight appropriately

Warning signs:

  • Rashes all over or persistent yeast rash
  • Reflux (lengthy crying spells, frequent spitting up, choking while feeding, aspirating)
  • Excessive gas
  • Begins chronic constipation or (explosive) diarrhea [after vaccinations]

Age: 4 MonthsThings your baby should be doing:

  • Smiling back at you when you laugh or smile
  • Making babbling sounds
  • Interested in looking at your face
  • Gaining weight appropriately
  • Typically can roll over
  • No apparent weakness on either side
  • Head is straight – not always tilted to one side
  • Eyes should now be straight
  • Having regular bowel movements

Warning signs:

  • Staring without following you or an object
  • No change in facial expression
  • Limited eye contact
  • Stops babbling after a period of babbling sounds
  • Food intolerances
  • Preoccupation with spinning objects (fans, wheels, etc.)
  • Begins repeat ear infections or chronic illnesses
  • Develops asthma or frequent upper respiratory infections
  • Frequent “colic” or extensive crying
  • Unusually “easy” baby, never fussing, never crying
  • Shows reaction to any vaccinations

Age 6 MonthsThings your baby should be doing:

  • Sit with assistance for a short time
  • Interested in activities of those around them
  • Beginning to show interest in food
  • Cooing and or babbling
  • Rolling over
  • Supporting weight on both legs with help
  • Waking only once per night if at all
  • Napping twice per day on a regular schedule

Warning signs:

  • No verbal sounds
  • Does not roll from side to side
  • If sitting and falls over, does not reach out with arms to catch her/himself
  • Has crossed eyes or other visual disturbance
  • Cries frequently for no reason

9 Months
Things your baby should be doing:

  • Showing interest in food
  • Crawling
  • Able to sit unassisted
  • Beginning to gesture or point
  • Express whether happy or sad by smiling or crying appropriately
  • Sleeping through most nights on a regular basis
  • Beginning to show signs of separation anxiety

Warning signs:

  • Headbanging on walls or floors or headbutting people
  • High tolerance to pain
  • Extreme sensitivity
  • Pushing head on carpet or along the wall
  • Wounded soldier crawl
  • Obsessed with a single toy or item (i.e. telephone, remote control) in place of toys
  • Not much interested in toys
  • Low muscle tone (hypotonia) or extreme (hyper-) flexibility
  • Hypertonia – extremely tense, rigid muscles
  • Not babbling with “baba,” “dada” sounds
  • Does not smile or laugh interactively
  • Appears to have hearing impairment
  • Frequent night waking
  • Chronic resistance to naps
  • Unconcerned with mother’s or father’s presence or lack there of
  • Chronically congested or chronic upper respiratory infections or ear infections

12 Months
Things your baby should be doing:

  • Able to understand most of what is said to him/her
  • Starting to stand unassisted, some even walking
  • Saying at least one word
  • Looking at your eyes when you speak to him/her
  • Able to understand yes and no
  • Pointing to objects
  • Making desires known
  • Beginning to eat or regularly eating solid foods
  • Waving hi and bye
  • Play peek-a-boo or patty-cake

Warning signs:

  • Obviously large head size in comparison to body
  • Does not point or otherwise gesture for objects
  • Avoids eye contact
  • Does not notice other children or siblings
  • Difficulty with transitions and/or new things
  • Excessive tantrums or aggressive behaviors
  • Unhealthy attachments to inanimate objects
  • Shows no interest in table food
  • Frequently gags, chokes, or shows sensory issues to texture
  • Easily and/or excessively irritated by tags on clothing or socks and shoes
  • Does not brace him/herself when falling
  • Afraid of the bathtub or water
  • Head seems excessively large

18 Months
Things your baby should be doing:

  • Walking steadily unassisted
  • Eating a varied diet of table food
  • Saying at least five or more recognizable words consistently
  • Understanding what you are saying
  • Making good eye contact
  • Laughing and smiling interactively
  • Playing with toys
  • Beginning to pretend play
  • Climbing over furniture, obstacles, etc., climbing up on things

Warning signs:

  • Frequently spinning in circles
  • Frequently walking on tiptoes
  • Licking the air or objects
  • Frequent self-stimulatory (stimming* or stim) behavior
  • Looks at things out of the corners of the eyes
  • Frequent uncontrollable and/or violent tantrums
  • Pinching, hitting, biting, or scratching repeatedly and/or frequently
  • Slamming (crashing) into furniture or people
  • Extremely sensitive
  • Extreme difficulty with transitions
  • Unusually long attention span (like for movies or TV)
  • Does not respond to name after repeated efforts
  • Fixated on television, computer, or other objects such as telephone or remote control
  • Self selected diet to gluten and casein or single foods
  • Consistently red ears and/or red cheeks
  • Afraid of loud noises
  • Covers ears
  • Does not allow you to brush his/her teeth
  • Fights having nails clipped
  • Easy gag reflex
  • Plays with same toy repetitively for extended amounts of time
  • Does not acknowledge other people or children
  • Refuses to get into car seat, arches back, tantrums
  • Hyperactive behavior
  • Excessive fascination and/or obsession with dinosaurs or trains (particularly Thomas the Tank engine)
  • Frequent sighing
  • Does not like fingers or toes touched
  • Delayed dentition (teeth)

24 Months
Things your baby should be doing:

  • Using at least 50+ words
  • Putting 2 – 3 words together
  • Interacting with other children
  • Eating a varied diet
  • Doing pretend play with sounds
  • Beginning to show interest in toilet training

Warning signs:

  • Limited diet of mac&cheese, chicken nuggets, and other wheat and dairy products
  • Echolalia – repeating words back sometimes seeming like they are answering you and then upset if it is not what they want (ex. You ask, “Do you want to go outside?” Child says, “Go outside.” You think this means they want to go outside so you take them outside. Toddler says, “No.” or has tantrum because s/he was not really answering but was repeating back what you said.
  • Scripting – repeating movie or TV lines – even in context
  • Obsessive compulsive behaviors – hand washing, checking things, shuffling feet, rituals
  • Underweight or height for age group (only in conjuction with other signs)
  • Insists on sameness or resistant to change
  • Difficulty expressing wants or needs
  • Repeats words or phrases
  • Excessive anxiety or irritable behaviors
  • Aloof
  • Overwhelmed in noisy, bright environments (like Jokers)
  • Frequently covers ears
  • Averse to singing or being sung to
  • Excessive laughing for no apparent reason
  • Excessive fear of strangers or relatives or
  • No fear of strangers
  • Chronic constipation or diarrhea
  • Continued resistance to toilet training
  • Feces smearing
  • Intolerance to clothing or removes clothing frequently
  • Hyper-sexual – excessive masturbation
  • Makes frequent loud noises or shrills and chirps
  • Wringing of hands or rocking behavior
  • Arm flapping
  • Maintains tilted head
  • Cannot jump
  • Cannot follow directions
  • Cannot express wants
  • Appears to be deaf at times
  • Hyperactive or inattentive
  • Oppositional and/or defiant (more so than usual for toddlers)
  • Lost words s/he used to say
  • Does not use inflection – monotone
  • Prefers to play alone
  • Does not play with toys
  • Does not smile back when smiled at
  • Does not like to cuddle or be touched
  • Does not like to have fingers, ears, or toes touched
  • Extreme independence
  • No regard for consequence (not upset by reprimand)
  • Precocious – developing or learning way ahead of peers with other warning signs
  • Showing signs of genius coupled with other warning signs
  • Unusual obsession with certain objects, subjects, or routines (ex. Must hold certain object at all times.)
  • In older children – trouble interpreting sarcasm – very literal
  • Delayed dexterity (uncoordinated, fine motor skills)
  • Apraxia – inability to make purposeful movements
  • Development of Tourette’s syndrome (facial and other tics, spontaneous noises)

*Stimming or stims are behaviors engaged in to self-sooth. They can be anything such as headbanging, spinning, rolling eyes, looking at things from the corners of the eyes, flapping arms, making noises, lining things up, shuffling feet, tapping, etc.