February 17, 2022

CDC Updates Developmental Milestones for Young Children

The Centers for Disease Control and Prevention (CDC) and the American Academy of Pediatrics (AAP) have revised developmental milestones for infants and young children in the Learn the Signs. Act Early. program, which helps parents identify autism and developmental delays in their children.

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According to a news release distributed by the CDC and the AAP, the previous developmental milestone checklists used 50th percentile, or average-age, milestones. Using this approach meant only half of children could be expected to achieve that milestone by that age. Thus, clinicians and families with concerns would at times choose a wait-and-see approach, leading to a delay in diagnosis.

The revised developmental milestones identify the behaviors that 75% or more of children can be expected to exhibit at a certain age based on data, developmental resources, and clinician experience.


Changes to the guidance include:

  • Adding checklists for ages 15 and 30 months; now there is a checklist for every well-child visit from two months to five years.

  • Identifying additional social and emotional milestones (e.g., Smiles on their own to get your attention, age four months).

  • Removing vague language like “may” or “begins” when referring to certain milestones.

  • Removing duplicate milestones.

  • Providing new, open-ended questions to use in discussion with families (e.g., Is there anything that your child does or does not do that concerns you?).

  • Revising and expanding tips and activities for developmental promotion and early relational health.

More Information

The process behind the revised milestones is detailed in an article titled “Evidence-Informed Milestones for Developmental Surveillance Tools” published in Pediatrics. Full resources and checklists are available on the CDC’s Learn the Signs. Act Early. page.