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Developmental Milestones

Developmental Milestones

Milestone tracking helps families organize observations about playing, learning, speaking, movement, and interaction. Milestone checklists do not replace standardized developmental screening.

Based on CDC · All sources · Checked November 3, 2026

Birth–5years is when developmental monitoring is especially importantCDC
9 · 18 · 30months: ages for general developmental screening at well-child visitsAAP, as described by CDC
1 in 5children aged 3–17 has one or more developmental disabilities (parent-reported)CDC · Pediatrics, 2026

What is developmental monitoring?

Developmental monitoring means watching how a child grows and changes over time — how they play, learn, speak, act, and move — to see whether they are reaching the milestones most children reach by a certain age. Parents, grandparents, child care providers, and other caregivers can all take part.

Monitoring, screening, and evaluation

Monitoring

Who: families, caregivers, and anyone who works with young children

What: watching for milestones over time

Why: helps organize questions and share progress with the doctor

Screening

Who: trained health care or early childhood professionals

What: a formal, validated questionnaire or checklist

Why: identifies possible concerns that need a closer look

Diagnostic evaluation

Who: a team of professionals experienced in diagnosing autism

What: a detailed assessment of development and behavior

Why: determines whether diagnostic criteria are met and guides support

Monitoring and screening work together; only a diagnostic evaluation can diagnose autism. Sources: CDC, NIMH.

How to track milestones

  • Use a free milestone checklist for your child’s age, or CDC’s free Milestone Tracker app.
  • Write down what you notice, with dates and examples.
  • Share your notes with your child’s doctor at every well-child visit.
  • If your child misses a milestone, talk with the doctor — don’t wait for the next visit.
Milestone checklists are not screening tools. They help you organize questions; they do not replace a standardized developmental screening. CDC milestone checklists.

This website provides general educational information. It does not diagnose autism or replace individualized medical, developmental, psychological, or educational advice. Screening is not diagnosis.

External listings do not imply affiliation, endorsement, or guaranteed services. Eligibility, availability, costs, and insurance coverage may change. Research summaries reflect evidence available at the time of review.