[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Behavioral science](https://durgical.com/en/behavioral-science/) › [Human development across the life span](https://durgical.com/en/behavioral-science/areas/development/) › Milestones of the first year

# Milestones of the first year

- Life stage

In the first year a baby goes from lifting the head to standing, from crying to first words, and from reflexes to purposeful play.

Updated Nov 5, 2026

## Key points

- 2 months: social smile, calms when spoken to or held, holds head up on tummy.
- 4 months: holds head steady without support, coos, brings hands to mouth.
- 6 months: rolls tummy to back, laughs, takes turns making sounds, reaches for toys.
- 9 months: sits without support, transfers objects hand to hand, babbles, wary of strangers, looks for a dropped or hidden object.
- 12 months: pulls to stand and cruises, pincer grasp, waves bye-bye, says mama or dada with meaning, understands no.
- CDC ages are when 75 % of babies show a skill; textbook averages (for example sitting at 6 months) are earlier.

## What it is

The first year is the fastest period of motor and social change. The ages below follow the CDC 2022 checklists, which list skills that at least 75 % of babies show by that age; classic textbooks often give earlier, average ages. Motor control progresses from head to feet, and the baby moves from reflexes to voluntary actions, social smiling and the first understanding of words.

## Key facts

- Head control comes before sitting, and sitting before standing (cephalocaudal sequence).
- The palmar grasp reflex fades and is replaced by voluntary grasp, then the raking grasp, then the pincer grasp near the first birthday.
- Stranger wariness near 9 months and searching for a hidden toy (object permanence) show that the baby now keeps people and objects in mind.
- Preterm babies are judged by corrected age.

## Milestones of the first year (CDC 2022 checklists)

| Age | Gross and fine motor | Language | Social and cognitive |
| --- | --- | --- | --- |
| 2 months | Holds head up on tummy; moves both arms and legs; opens hands briefly | Makes sounds other than crying; reacts to loud sounds | Social smile; looks at faces; follows a person moving |
| 4 months | Holds head steady when held; holds a toy placed in the hand; pushes up on forearms | Coos; makes sounds back; turns toward a voice | Smiles to get attention; chuckles; looks at own hands |
| 6 months | Rolls tummy to back; pushes up on straight arms; leans on hands to sit | Takes turns making sounds; blows raspberries; squeals | Recognizes familiar people; laughs; explores objects with the mouth |
| 9 months | Sits without support and gets into sitting alone; transfers objects; rakes food | Babbles many sounds; lifts arms to be picked up | Shy or fearful with strangers; responds to name; looks for dropped objects |
| 12 months | Pulls to stand; walks holding furniture; pincer grasp (thumb and index) | Waves bye-bye; mama or dada with meaning; understands no | Plays pat-a-cake; looks for hidden objects; puts objects in a container |

## Clinical notes

- Not holding the head steady by 4 months, not rolling or reaching by 6 months, or not sitting by 9 months calls for evaluation, including tone and reflexes.
- A clear hand preference before 12 months suggests weakness of the other side (for example hemiplegic cerebral palsy).
- No reaction to loud sounds or no babbling suggests hearing loss; newborn hearing screening does not rule out later loss.

## Memory aid

Head at 4, roll at 6, sit at 9, stand at 12: the body climbs one floor at a time.

## Test yourself

Think of the answer, then tap the question to see it.

## By what age do most babies (75 %) sit without support according to the CDC checklists?

By 9 months. Classic averages say about 6 months, but the CDC lists the age most babies have reached.

## Which fine motor skill is expected by 12 months?

The pincer grasp: picking up small objects between the thumb and index finger.

## What does stranger wariness at about 9 months show?

That the baby recognizes familiar people and keeps them in mind; it goes with the first signs of object permanence and attachment.

## Why is hand preference in the first year a red flag?

Babies normally use both hands; a strong preference this early suggests weakness of the other side, for example hemiplegic cerebral palsy.

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## Elsewhere in DurgiPedia

- [Pediatric history: perinatal, growth, development and vaccines](https://durgical.com/en/clinical-exam/pediatric-history-perinatal-growth-development-and-vaccines/)
- [Newborn physiology and fetal maturation](https://durgical.com/en/physiology/newborn-physiology-and-fetal-maturation/)

## Connections

## Related 7

- [Developmental milestones: domains, corrected age and red flags](https://durgical.com/en/behavioral-science/developmental-milestones-domains-corrected-age-and-red-flags/)
- [Milestones from 1 to 3 years](https://durgical.com/en/behavioral-science/milestones-from-1-to-3-years/)
- [Milestones from 4 years to school age](https://durgical.com/en/behavioral-science/milestones-from-4-years-to-school-age/)
- [Primitive reflexes and when they disappear](https://durgical.com/en/behavioral-science/primitive-reflexes-and-when-they-disappear/)
- [Attachment: Bowlby, Ainsworth and the attachment styles](https://durgical.com/en/behavioral-science/attachment-bowlby-ainsworth-and-the-attachment-styles/)
- [Piaget's stages of cognitive development](https://durgical.com/en/behavioral-science/piaget-s-stages-of-cognitive-development/)
- [Temperament](https://durgical.com/en/behavioral-science/temperament/)

## Related conditions 4

- [Cerebral palsy](https://durgical.com/en/conditions/cerebral-palsy/)
- [Hearing loss (conductive and sensorineural, including sudden hearing loss)](https://durgical.com/en/conditions/hearing-loss/)
- [Prematurity and its complications](https://durgical.com/en/conditions/prematurity-and-its-complications/)
- [Down syndrome (trisomy 21)](https://durgical.com/en/conditions/down-syndrome/)

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Educational content on behavior and the clinical relationship; not a diagnostic or treatment guide and no substitute for assessment by a health professional. If you or someone near you is at risk, seek help now from an emergency service or a mental-health helpline.

Sources: [Milestones by 2 Months](https://www.cdc.gov/act-early/milestones/2-months.html) (Centers for Disease Control and Prevention (CDC), 2026); [Milestones by 6 Months](https://www.cdc.gov/act-early/milestones/6-months.html) (Centers for Disease Control and Prevention (CDC), 2026); [Milestones by 9 Months](https://www.cdc.gov/act-early/milestones/9-months.html) (Centers for Disease Control and Prevention (CDC), 2026); [Milestones by 1 Year](https://www.cdc.gov/act-early/milestones/1-year.html) (Centers for Disease Control and Prevention (CDC), 2026).

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