🌱 Developmental stages

🍼Infant

From one month to twelve months — motor milestones, first foods, attachment deepening, and emerging sleep patterns.

Also called: Baby · First year

Media credits

Six-month-old infant sitting with support
Kimberly Vardeman · CC BY 2.0

Quick facts

1–12 monthsAge span
Rolls ~4–6 moMotor
WHO ~6 mo startSolids
12–16 hrs/daySleep
Babbling ~6–9 moWords
Stranger anxiety ~8 moAttachment

The infant year spans rapid motor, cognitive, and social growth from dependent newborn to mobile, communicative near-toddler.

Piaget's sensorimotor stage and later attachment research frame this period as active learning through movement, mouth, and reliable caregivers.

WHO complementary feeding guidance, AAP safety standards, and global vaccination schedules intersect with daily parenting choices.

The profile

909678258580
  • Evidence strength90
  • Daily impact96
  • Difficulty78
  • Age span25
  • Expert consensus85
  • Urgency80

Age range

80 / 100

1–12 months

From one month to twelve months — motor milestones, first foods, attachment deepening, and emerging sleep patterns.

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Frequently asked questions

When do infants roll over?
Many roll front-to-back between 4–6 months; wide normal range exists — tummy time supports development.
When start solid foods?
WHO and AAP recommend around six months when sitting with support and showing interest — not before four months.
Is teething causing fever?
Mild drooling and gum irritation yes; high fever usually has another cause and needs medical review.
When can infants sleep through the night?
Some sleep longer stretches by 6–9 months; many still wake for feeds or comfort — biologically normal.
How important is tummy time?
Daily supervised tummy time builds neck and shoulder strength for crawling and reduces flat head spots.
When stranger anxiety?
Often peaks 8–10 months as attachment to primary caregivers solidifies — not shyness to "fix".
Are walkers safe?
AAP discourages infant walkers due to fall and stair injury risk; stationary activity centres are safer.
How many words by one year?
A few words or consistent gestures are typical; range is wide and bilingual infants may later on both languages.

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