TinySteps

Evidence-Based Infant & Toddler Care

Development

Month-by-month developmental milestones from 2-36 months, red flags to watch for, M-CHAT-R autism screening, and when to seek evaluation.

Developmental Milestones

AgeMotorSocialLanguageRed Flags
2 monthsHolds head up brieflySocial smileCoos, gurglingNo social smile, cannot hold head up
4 monthsSteady head, pushes up on elbowsLaughs, enjoys playBabbles, copies soundsNo head control, no sounds
6 monthsRolls both ways, sits with supportKnows familiar vs strangersResponds to name, vowel stringsDoes not reach, no affection
9 monthsSits alone, crawls, pulls to standClingy, favorite toysUnderstands "no," copies gesturesCannot sit, no peek-a-boo
12 monthsPulls to stand, may walkCries when parent leaves1-3 words, "mama/dada" specificallyNo babbling, no gestures
18 monthsWalks, climbs, drinks from cupSimple pretend play6-20 words, points to body partsNot walking, <6 words
24 monthsRuns, kicks ball, walks stairsParallel play, copies adults50+ words, 2-word phrasesNo 2-word phrases, <50 words
36 monthsPedals tricycle, runs easilyTakes turns, shows concernSentences, asks "why?", 200-1000 wordsUnclear speech, no sentences

M-CHAT-R Autism Screening

Administered at 18 and 24 month well-visits. 20 yes/no questions. Sensitivity ~85% for ASD, specificity ~99% with follow-up.

Key Screening Questions