Early Signs of Autism in Babies and Toddlers, and How Screening Works

The basics

• Autism is a difference in how the brain develops that affects social communication and often includes repetitive behaviors or strong focused interests. It's a spectrum: children's strengths and needs vary widely.
• Recent CDC estimates put it at roughly 1 in 31 children in the US. Boys are diagnosed more often, and girls are sometimes missed.
• Signs often show between about 12 and 24 months. Autism can be reliably diagnosed by a specialist by age 2, though many children are diagnosed later.
• Parenting doesn't cause autism. Genetics play a large role. Large studies of millions of children have found no link with vaccines, and the AAP continues to stand by that evidence.

Signs worth noticing

No single sign means autism, and many children without autism show one or two of these. - By 9 months: rarely responds to their name; few facial expressions like happy, sad or surprised; little back-and-forth sharing of sounds and smiles. - By 12 months: no simple interactive games like peekaboo; few or no gestures, such as waving bye-bye or reaching up to be picked up. - By 15 to 18 months: doesn't point to show you something interesting; doesn't bring toys to share; doesn't look where you point. - By 24 months: doesn't notice when others are hurt or upset; few or no two-word phrases. - By 30 months: little pretend play, like feeding a doll. - At any age: lining up toys in the same way and getting very upset if they're moved; repeating words or phrases; strong reactions to sounds, textures or smells; hand flapping, rocking or spinning; intense distress at small changes in routine; little eye contact. - Loss of words, babbling or social skills at any age is always worth raising soon.

How screening works

• The AAP recommends autism-specific screening at the 18 and 24 month well visits, plus general developmental screening at 9, 18 and 30 months. Most practices use a short parent questionnaire, often the M-CHAT-R/F, followed by a few questions from the clinician.
• A screen is not a diagnosis. A "positive" result means a closer look is needed. A "negative" result doesn't override your concerns.
• You can ask for a screen at any visit, at any age.

If you're worried

1. Write down what you see, with examples and short videos if you can.
2. Talk to the pediatrician and ask for a screen and a referral for a developmental evaluation, plus a hearing test.
3. Contact early intervention yourself while you wait (under 3) or your public school district (3 and up). You don't need a diagnosis or a referral to request a free evaluation. See the early intervention explained guide.

A calm view

• Many children who show a sign or two turn out to be developing typically, and many autistic children thrive. Early support helps with communication and daily life, and with understanding your child.

When to check in

• Mention it at the next checkup if any of the signs above fit your child, or if something just feels different to you.
• Bring it up soon, without waiting for the next routine visit, if your child loses words or social skills they had.