If you've started quietly googling at midnight — should my baby be doing this by now? — this article is for you. The goal here isn't to diagnose anything or to frighten you. It's to help you notice gently, understand what pediatricians actually look for, and know that asking a question early is a normal, smart thing to do.
The guiding idea, in the CDC's own words, is "act early, not wait and see." Let's unpack what that means.
How screening actually works
Autism screening is a built-in part of routine well-child care — not something reserved for kids whose parents are worried. The American Academy of Pediatrics recommends:
- General developmental screening at 9, 18, and 30 months
- Autism-specific screening at the 18- and 24-month well-child visits
The common tool for that autism-specific screen is the M-CHAT-R/F — the Modified Checklist for Autism in Toddlers, Revised with Follow-Up. It's a short parent questionnaire for children ages 16 to 30 months, and you've likely filled one out without realizing what it was.
Here's the most important thing to understand about it: a positive screen is not a diagnosis. It means "let's get a fuller evaluation" — a flag to look more closely, nothing more. Plenty of children who screen positive turn out not to be autistic. Screening is designed to catch concerns early so they can be properly assessed, not to label anyone.
Early signs the CDC suggests watching for
The CDC's "Learn the Signs. Act Early." program highlights social-communication patterns that are worth a conversation with your pediatrician. Keep in mind these are signs to discuss, not a checklist that adds up to a diagnosis. A child may show one and be perfectly on track.
According to the CDC, early signs can include:
- Not responding to their name by around 9 to 12 months. (We go deeper on this in why your baby may not respond to their name.)
- Few or no gestures — like not waving bye-bye by 12 months, or not pointing to show you something by 18 months.
- Little eye contact.
- Not playing simple pretend — feeding a doll, talking on a toy phone — by around 18 to 24 months.
- Losing skills they once had (regression) — for example, a child who used to say a few words or wave, and then stops.
Importantly, the timing varies a lot. Some children show signs in the first year; others not until 24 months or later. There's no single moment when signs "should" appear.
Why milestones are framed the way they are
You may have noticed milestone checklists changed in recent years. The CDC's lists now describe skills that about 75% of children reach by a given age. That's deliberate: if three out of four children can do something by a certain age and yours can't, that's a reasonable, low-drama prompt to ask about it — rather than waiting until a much later "average" has passed.
This is the whole logic of "act early." The earlier a child gets support, the more it can help — because the early years are when the brain is most adaptable. Noticing early doesn't label your child. It simply opens the door to help sooner. For the broader picture, see our guide to developmental red flags and early intervention.
When to talk to your pediatrician
The honest answer: whenever something is nagging at you. You do not need to be sure. You do not need a list of three signs. Trust your gut and bring it up — that's exactly what your pediatrician is there for.
Reach out if you notice:
- Your child isn't responding to their name by around their first birthday
- No pointing, waving, or other gestures by 12 to 18 months
- Loss of skills your child previously had
- Little eye contact or limited back-and-forth social engagement
- Any milestone on a CDC checklist your child hasn't reached for their age
- Simply a persistent feeling that something is different
If your pediatrician shares a concern, the next step is usually a fuller developmental evaluation — and, where appropriate, early intervention services, which are often free or low-cost and don't require a diagnosis to begin.
A calm, reassuring close
Noticing early is an act of care, not alarm. Most children flagged by a screen are evaluated and reassured; for the children who do need support, starting early is the single best thing you can do. Either way, you win by asking.
So if that midnight worry is real, write it down and bring it to your next visit. You don't have to have the answer — you just have to ask the question. You don't need to be sure to ask.