Developmental Milestones for a 4-Month-Old Infant
At 4 months of age, infants should demonstrate rolling from prone to supine, supporting themselves on elbows/wrists when on their stomach, keeping hands unfisted, playing with fingers at midline, and grasping objects. 1
Gross Motor Skills
- Rolling prone to supine is the key gross motor milestone expected at 4 months, representing advancement from the 2-month ability to simply lift head and chest 1
- Supporting on elbows and wrists in prone position demonstrates improved upper body strength and postural control 1
- Infants at this age should have well-established head control, building on the head lifting achieved at 2 months 1
Fine Motor Skills
- Hands should be unfisted most of the time, marking a significant change from the fisted hands typical of younger infants 1
- Playing with fingers at midline demonstrates emerging hand awareness and bilateral coordination 1
- Grasping objects when presented is expected, representing the first true fine motor milestone (whereas no specific fine motor skills were expected at 2 months) 1
Cognitive and Sensory Development
- At 4 months, infants develop predictive control of actions and can coordinate their behavior with ongoing events in the world 2
- Out of sight is no longer out of mind at this age, as infants begin to understand object permanence 2
- Smooth-pursuit eye movements mature during this period, and infants can predict when and where an occluded moving object will reappear 2
Clinical Surveillance Considerations
- The American Academy of Pediatrics recommends continuous developmental surveillance at every visit, with parents' concerns about development being elicited and documented 1
- For infants born before 36 weeks gestation, correct for prematurity for at least the first 24 months when assessing milestones 1, 3
- Marked delays beyond expected ages warrant attention, though some variation is normal and delays do not necessarily signify neuromotor disease 1
Red Flags Requiring Immediate Evaluation
- Loss of previously acquired skills (regression) warrants immediate evaluation for progressive disorders 4
- Asymmetry in movement patterns may indicate unilateral cerebral palsy and requires prompt assessment 4
- Inconsistent or absent head control at 4 months suggests possible weakness or abnormal tone 4
- Hypotonia, feeding difficulties, or dysmorphic features warrant earlier subspecialist referral 4
Assessment Tools and Follow-Up
- Standardized developmental screening instruments can be administered at this age, with evidence-based milestone questions available for systematic surveillance 5, 6
- Early identification of developmental delays allows for referral to therapeutic services, and children referred for early intervention are more likely to make gains in developmental milestones 3
- If concerns arise, immediate referral to early intervention services should occur even before a specific diagnosis is established 4