(HealthDay)—Screen your young child early and often for developmental delays.

That's the message behind updated checklists from the U.S. Centers for Disease Control and Prevention and the American Academy of Pediatrics (AAP).

The checklists, revised for the first time since their release in 2004, outline developmental milestones for infants and young children, to help identify delays earlier, and are part of regular checkups by pediatricians.

The checklists previously used 50th percentile milestones, meaning only half of children were expected to achieve the milestone at a given age. The updated checklists ask about milestones 75% or more of children can be expected to achieve by a certain age.

"The earlier a child is identified with a developmental delay the better, as treatment as well as learning interventions can begin," Dr. Paul Lipkin, a member of the AAP Section on Developmental and Behavioral Pediatrics and Council on Children with Disabilities who assisted with the revisions, said in a news release.

"At the same time, we don't want to cause unnecessary confusion for families or professionals. Revising the guidelines with expertise and data from clinicians in the field accomplishes these goals," Lipkin added.

Other changes include:

• Added checklists for children at ages 15 and 30 months. There is now a checklist for every checkup visit from 2 months to 5 years of age.

• Additional social and emotional milestones, including smiling on their own to getting your attention at 4 months old.

• New, open-ended questions for use in discussions between parents and pediatricians, such as, is there anything that your child does or does not do that concerns you?

• Revised and expanded advice and activities to promote kids' development.

While she's pleased to see the checklists updated, developmental behavioral pediatrician Dr. Jenny Radesky, from the University of Michigan's C.S. Mott Children's Hospital, said parents should remember that milestones are not everything.

Parents should also rely on their own personal knowledge of their children, including what brings them joy, what overstimulates them, and when parents feel most connected to them.

"These aspects of parent-child relationship are not measured through milestones, but are crucial to children's mental well-being," Radesky told CNN.

More information: Visit the U.S. Centers for Disease Control and Prevention for more on childhood milestones.

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