👤 By the CinnaRN Clinical Content Team🕐 Updated 2026-08-23🏷️ Health Promotion & Maintenance🔖 Free to read, print, and share
Also known as: baby milestones · child development chart · motor and language milestones
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Use this quick-reference guide to spot, treat, and prevent Developmental Milestones by Age on the NCLEX. Keep it handy during review and on exam day!
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📒 The 1-minute cheat sheet
📌 Infant
2mo: social smile
6mo: sits w/ support, rolls
12mo: walks, 1-2 words
📌 Toddler
18mo: runs, ~10 words
2yr: 2-word phrases, stairs
3yr: tricycle, 3-word sentences
📌 Preschool
4yr: hops, draws person
5yr: skips, ties shoes
🚩 Red Flag
No smile 3mo, no sit 9mo
No walk 18mo, no words 16mo
Loss of skill = refer now
📚 Developmental Milestones by Age — full study notes
The cheat sheet above is your quick recall card. These notes go deeper — what it is, what to do first, what must be reported, and what to teach.
Developmental milestones are expected motor, language, social, and cognitive skills achieved by a given age. They screen for normal development and detect delays early. Development proceeds cephalocaudal (head to toe) and proximodistal (center to periphery).
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Key points
Understand these first
2 months: social smile and lifts head; 4 months: rolls; 6 months: sits with support and transfers objects.
9 months: sits unsupported and crawls; 10 months: pincer grasp; 12 months: stands, says first words, walks with help.
By age 2 a child should know about 50 words; by age 3 speech is mostly understandable to strangers.
Birth weight doubles by about 5-6 months and triples by 12 months.
The posterior fontanel closes by 2-3 months; the anterior fontanel closes by 12-18 months.
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Nursing priorities
What to do, in order
Use a standardized tool to screen development at well-child visits and plot growth.
Assess head circumference, weight, length, and fontanels at each infant visit.
Counsel parents on age-appropriate stimulation, play, and safety.
Refer for early intervention promptly when a delay or red-flag finding is identified.
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Red flags — report now
Escalate immediately
No social smile by 3 months, not sitting by 9 months, or not walking by 18 months requires evaluation.
Loss of previously acquired skills (regression) is reported and evaluated for a neurologic cause.
A bulging fontanel (increased intracranial pressure) or a sunken fontanel (dehydration) is reported now.
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Labs & values
Numbers to know
Head circumference, length, and weight plotted on growth charts (track percentile and trend)
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Patient teaching
What patients must know
Provide tummy time while awake and always place infants on their back to sleep.
Read and talk to children daily to support language; limit screen time in young children.
❓ Developmental Milestones by Age: NCLEX FAQs
What are the priority nursing interventions for Developmental Milestones by Age?
Use a standardized tool to screen development at well-child visits and plot growth. Assess head circumference, weight, length, and fontanels at each infant visit. Counsel parents on age-appropriate stimulation, play, and safety. Refer for early intervention promptly when a delay or red-flag finding is identified.
What are the warning signs of Developmental Milestones by Age a nurse must report?
No social smile by 3 months, not sitting by 9 months, or not walking by 18 months requires evaluation. Loss of previously acquired skills (regression) is reported and evaluated for a neurologic cause. A bulging fontanel (increased intracranial pressure) or a sunken fontanel (dehydration) is reported now.
What do I need to know about Developmental Milestones by Age for the NCLEX?
2 months: social smile and lifts head; 4 months: rolls; 6 months: sits with support and transfers objects. 9 months: sits unsupported and crawls; 10 months: pincer grasp; 12 months: stands, says first words, walks with help. 15 months: walks independently; 2 years: runs, climbs stairs, and uses 2-word phrases. By age 2 a child should know about 50 words; by age 3 speech is mostly understandable to strangers.
What patient teaching is important for Developmental Milestones by Age?
Provide tummy time while awake and always place infants on their back to sleep. Read and talk to children daily to support language; limit screen time in young children.
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Quick Tip
2 months: social smile and lifts head; 4 months: rolls; 6 months: sits with support and transfers objects.