Infant Development Stages

Socialization and Vocalization

• Infants make throaty sounds and show interest in human faces

Cognitive and Emotional Development

• Infants develop reflexively, responding to external stimuli without meaning
• According to Erikson, infants develop a sense of trust vs. mistrust from birth to 1 year
• According to Freud, infants are in the oral stage from birth to 1 year
• According to Piaget, infants are in the sensorimotor period from birth to 2 years

Physical Growth

• Growth of head:
  • Posterior fontanel closes at 2 months
  • Anterior fontanel closes at 1-2 years
  • Head circumference increases by 2 cm by the end of the first month
  • Average head circumference at birth: 33-35 cm
  • Average head circumference at 5 years: 50 cm
• Growth of chest and abdomen:
  • Chest and abdomen circumference are equal at the end of the first year
  • Abdomen is prominent in infants and young children
• Growth in length:
  • Neck and extremities are relatively short
  • Head is relatively large
  • Infant gains 2 cm/month in length during the first 6 months
  • Infant gains 1.5 cm/month in length during the second 6 months
• Gain in weight:
  • Average birth weight: 3.5 kg
  • Weight doubles between 4th and 5th months
  • Weight triples by the end of the first year
  • Infant gains 3/4 kg/month in weight during the first 4 months
  • Infant gains 1/2 kg/month in weight during the second 4 months
  • Infant gains 1/4 kg/month in weight during the last 4 months
• Chest circumference:
  • At birth, head circumference is 2 cm larger than chest circumference
  • Between 1 and 2 years, both are equal
  • After 2 years, chest circumference is larger than head circumference

Development of Newborn

• Physical growth:
  • Weight: 2.7-4 kg at birth, loses 5-10% of weight by 3-5 days, and gains birth weight by 10th day
  • Height: Average boy's height is 50 cm, average girl's height is 49 cm
  • Head circumference: 33-35 cm
• Physiological growth:
  • Temperature: 36.4-37.4°C
  • Pulse: 120-150 beats/minute
  • Respiration: 35-50 breaths/minute
• Development:
  • Gross motor: lies flexed with knees under abdomen in prone position
  • Fine motor: hands are closed most of the time, keeps hands fisted

Development of Infant

• Age and growth motor development:
  • 1 month: raises head momentarily
  • 2 months: raises chin off couch when prone
  • 3 months: head supported, can hold a rattle if placed in hand
  • 4 months: sits with support, brings hands together
  • 6 months: sits without support, reaches objects and brings them to mouth
  • 9 months: stands with support, can use thumb and finger to pick cube
  • 12 months: stands freely, throws objects, walks with one hand held, holds cup to drink
• Cognitive and language development:
  • 1 month: vocalizes (not crying)
  • 2 months: is interested in environment
  • 3 months: aware of strange situations
  • 4 months: recognizes bottle and is more interested in mother
  • 6 months: recognizes mother and chews
  • 7 months: indiscriminate Da-Da, M-m
  • 9 months: imitates speech sounds
  • 12 months: says 2-3 words, understands several words

Causes of Delayed Development

• Delayed smiling:
  • Lack of stimulation
  • Mental subnormality
  • Blindness
  • Autism
• Delayed sitting and walking:
  • Familial features
  • Rickets
  • Mental subnormality
  • Cerebral palsy
  • Poliomyelitis
  • Muscular dystrophy
  • Emotional deprivation