What are the expected developmental milestones for children from birth to five years of age?

Pediatric Developmental Milestones: Birth to 5 Years

Core Motor Milestones by Age

The American Academy of Pediatrics provides specific mean ages for motor milestone achievement that should guide developmental surveillance at every well-child visit. 1

Gross Motor Development

• 2 months: Lifts head and chest when lying on stomach 1
• 4 months: Rolls from stomach to back; supports weight on elbows and wrists in prone position 1
• 9 months: Rolls from back to stomach; sits without support; pulls to stand; crawls; transitions from lying to sitting 1
• 12 months: Walks independently; stands without support 1
• 18 months: Walks backward; runs; walks up steps with hand held 1
• 2 years: Rides on toy without pedals; jumps up 1
• 2.5 years: Begins walking up steps alternating feet 1
• 3 years: Pedals tricycle; climbs on and off furniture independently 1
• 4 years: Climbs stairs without support; skips on one foot 1

Fine Motor Development

• 4 months: Hands unfisted; plays with fingers at midline; grasps objects 1
• 9 months: Reaches for cubes and transfers between hands; rakes small objects with 4 fingers; picks up small objects with 3 fingers 1
• 12 months: Puts 1 block in cup; bangs 2 objects together; uses 2-finger pincer grasp for small objects 1
• 18 months: Scribbles in imitation; dumps small objects from bottle (first with demonstration, then spontaneously); builds tower of 2 cubes; scribbles spontaneously; puts 10 blocks in cup 1
• 2 years: Builds tower and horizontal train with 3 blocks 1
• 2.5 years: Imitates horizontal and vertical lines; builds train with chimney using 4 blocks 1
• 3 years: Copies a circle; draws person with head and one other body part; builds bridge with 3 blocks 1
• 4 years: Draws person with 6 parts; draws simple cross; buttons medium-sized buttons 1

Language and Communication Milestones

Early language skills are the strongest predictor of later IQ, more so than other cognitive domains, making language surveillance critically important. 2

Key Language Markers

• Language development can be reliably monitored using 26 empirically-validated milestones covering vocabulary, grammar, and communication from ages 1-6 years 3
• Language skills predict children with intellectual disability as early as 8 months and gifted children from 12 months 2
• By 24 months, developmental milestones predict approximately 20% of later IQ variance, with language being the dominant predictor 2

Cognitive and Social-Behavioral Development

For toddlers and preschoolers (1-5 years), monitor these specific domains: cognitive, gross motor, fine motor, communication (speech, expressive/receptive language, pragmatics), adaptive skills, and social-behavioral interactions. 1

Critical Surveillance Points

• Maintain close surveillance for autism spectrum disorder symptoms throughout the toddler and preschool years 1
• Formal evaluation before kindergarten entry (ages 3.5-5 years) optimizes identification and planning of educational supports 1
• Any sign of developmental regression (not just delay) warrants immediate investigation for progressive disorders 1

Red Flags Requiring Immediate Action

These findings mandate standardized investigations and specialist referral: 4

• Inability to sit independently by 9 months 4
• Asymmetry in hand function at any age 4
• Inability to bear weight through plantar surface of feet when expected 4
• Loss of previously acquired skills (regression) 1
• Marked delay beyond mean milestone ages listed above 1

Surveillance Schedule and Screening

Continuous developmental surveillance should occur at every visit, with standardized developmental screening performed at 9,18, and 30 months, plus whenever concerns arise. 1

Surveillance Components

The American Academy of Pediatrics defines five essential surveillance components: 1

• Elicit and attend to parents' concerns about development 1
• Document and maintain developmental history 1
• Make accurate observations of the child 1
• Identify risk and protective factors 1
• Maintain accurate developmental records 1

When to Refer

Refer to developmental pediatrician, pediatric neurologist, or pediatric psychologist when: 1

• Standardized screening identifies delays 1
• Parent or provider concerns persist despite normal screening 1
• Child has high-risk conditions (congenital heart disease, prematurity, genetic syndromes) 1
• Speech and language impairments are detected 1

Age-Specific Assessment Approaches

Infants (Birth to 12 Months)

Formal evaluation should include: 1

• Systematic comparison to appropriate milestones 1
• Growth measurements: height, weight, BMI, head circumference 1
• Feeding assessment (feeding difficulties are common in high-risk infants) 1
• Neuromotor examination: passive/active muscle tone, primitive and deep tendon reflexes, sensory status, gross motor quality 1, 4
• Audiologic examination if hearing loss suspected or no neonatal screening documented 1

Toddlers and Preschoolers (1-5 Years)

Use standardized measures providing scores in cognition, receptive/expressive language, and fine/gross motor skills. 1

• Formal speech-language pathologist evaluation for any speech/language impairments 1
• Parent report of behavior to detect behavioral problems and social competence delays 1
• Evaluation at 3.5-5 years before kindergarten entry is essential 1

Critical Caveats

Important limitations and considerations:

• These milestone ages represent mean performance; individual variation exists, but marked delays warrant attention 1
• Developmental milestone checklists vary significantly in content overlap (only 5.5% of milestones appear across all major checklists) and age concordance 5
• Preschool or childcare staff concerns about motor development must be addressed 1
• Early intervention services (birth to 3 years) are mandated by federal law for children with developmental delays or established risk conditions 1
• Parent-completed screening tools are valid and time-efficient for primary care settings 6