Developmental Milestones & Flags, Birth to School Age
Version 1.0 · Last reviewed July 2026 · Review cadence: Quarterly
2 months — Smile socially; calm when spoken to; briefly lift the head during tummy time; make sounds other than crying.
6 months — Roll over (front to back); push up on straight arms during tummy time; take turns making sounds; reach for toys.
9 months — Sit without support; pass objects hand to hand; look for a dropped object; show several facial expressions; respond to her name.
12 months — Pull to stand and cruise; wave “bye-bye”; say “mama” or “dada” with meaning; put objects in a container.
18 months — Walk well; use several single words; point to show interest; follow a one-step direction; copy a chore.
2 years — Run; use two-word phrases; follow two-step instructions; kick a ball; begin pretend play.
3 years — Speak in short sentences understood by others most of the time; pedal a tricycle; play alongside and with other children.
4–5 years — Tell a simple story; hop; draw a person with several body parts; follow rules in simple games; dress with little help.
THE CAREGIVER’S JOB WITH MILESTONES
Observe and document, share patterns with the family, and act early if something seems off — but never diagnose. “Act Early” means a developmental concern is raised with the family and the pediatrician promptly, because early intervention works best the earlier it starts. The free Early Intervention program in every state evaluates children under 3 at no cost to the family.
Age-by-age domain tables with caregiver supports and flag lists: Volume 1, Unit 2. Milestones support monitoring, never diagnosis.