Baby missing milestones: what to do in the first year

What does the evidence show for missing developmental milestones in the first year?

• CDC's Learn the Signs. Act Early. program provides milestone checklists at 2, 4, 6, 9, and 12 months in the first year, covering skills like taking a first step, smiling for the first time, and waving bye-bye. If a child is not meeting one or more milestones or has lost skills they once had, CDC advises acting early and talking with the child's doctor rather than waiting to see. 1
• The core message of the program is to track a child's development from birth through age 5 and act early on any concern, backed by free resources built around ongoing monitoring rather than a single checkpoint. 2
• If milestones are missed, the recommended path is concrete: discuss milestones reached and expected next steps at every pediatric visit, use milestone checklists to describe specific concerns, ask the doctor about developmental screening, request a specialist referral if concerns continue, and contact early intervention programs directly for children under 3, or the local public school system for children 3 and older, for a free evaluation. 3
• Developmental surveillance should happen at every well-child visit. The American Academy of Pediatrics recommends standardized developmental screening at 9, 18, and 30 months, with autism-specific screening at 18 and 24 months, and clinicians are advised to account for corrected age when assessing babies born prematurely. 4
• A specific condition does not need to be identified before a referral to Early Intervention, and parents can request that referral themselves rather than needing a doctor to initiate it first. Early Intervention services can include speech, physical, and occupational therapy support, along with service coordination and family support. 4
• Tracking milestones is framed as a way to help families stay in tune with a child's developmental health and identify concerns early enough that a child has a better chance of getting support and reaching their full potential, rather than a pass-or-fail check at each visit. 3

When should I call my provider about missing developmental milestones in the first year?

Losing a skill your baby previously had, sometimes called regression, is specifically named by CDC as a reason to act early and talk with your child's doctor, separate from simply not having reached a new milestone yet. Missing several milestones at once, or across more than one area of development at the same time, is a reason to ask directly about a full developmental screening rather than monitoring quietly at home. Trust a persistent gut-level concern even if a single checklist item looks fine, since CDC's core guidance is to act on any concern rather than wait for it to resolve on its own. When in doubt, call your obstetric team the same day. Early input almost always beats waiting, and the on-call line exists exactly for this.