creation date: 2025-05-01 21:34
tags: Anatomy & Physiology
Infant Growth
Background
Infant Developmental Milestones
Most notable:
- 2m: cooing, social smile
- 4m: rolls front to back, reaches and obtains items, laugh
- 6m: sits tripod, transfers hand to hand, stranger anxiety (looks at stranger weird)
- 9m: creeps on hands and knees, mama/dada, gestures byebye/up, object permanence, peek-a-boo, separation anxiety (cries away from parents)
- 12m: walks few steps, fine pincer, 1 word with meaning, 1 step command with gesture, imitates gestures and sounds
Feeding
Between 0-3 Months
Infant is breastfed or formula fed every 3-4 hours.
- Vitamin D supplementation if breast-fed
After 4-6 Months
Can start introducing solids if:
- Interested in food
- Can sit without support
- Diminished tongue thrust reflex
Food should include:
- Iron rich food as first options
- Iron supplementation if iron deficient
- Allergens early, one at a time; wait 2 days in between each to allow for time for adverse reaction identification
- Vitamin D supplementation while breastfeeding exclusively
- Avoid unpasteurized foods (eg. honey)
Introduction should not delay beyond 9 months for oral motor development.
9-12 Months
Encourage self-feeding and open cup by 12 months.
Foods include:
- Switch to homogenized cow’s milk
- Iron rich foods, vegetables, fruits, grains first, then milk or water
- Provide up to 3 meals a day with 1-2 snacks at set times
12-24 months
Discontinue bottle use. Honey may be considered after 12 months.
Foods to avoid include:
- Added sugar/salt
- Excessive milk (max 500 mL/d after 1 year) to avoid iron deficiency anemia
- Juice (high sugar)
- Choking hazards
Stooling and Urination
Physical Growth
Weight
At birth (term baby):
- Birthweight average 3-3.5 kg
- Neonates may lose 7-10% of weight after birth
- Should regain birth weight by 10-14 days
- 30g per day
Afterwards:
- Double weight by 4-5 months
- Triple weight by 1 year old (average 10 kg)
- Quadruple weight by 2 years old
- Gain 2 kg/year until age 6
Length/Height
At birth (term baby):
- 50 cm long
Normal growth velocity:
- 24 cm/yr for first year
- 12 cm/yr for 2nd year
- 8 cm/yr for 3rd year
- 6 cm/yr for childhood
- 8-12 cm/yr for adolescence
Height doubles by 4 years.
Head Circumference
At birth (term baby):
- Average is 35 cm
- <32 cm is microcephalic
- Note, measurement may be inaccurate due to caput or molding
Afterwards:
- Increase by 2 cm/month for first 3 months
- Increase by 1 cm/month for months 3-6
- Increase by 0.5 cm/month for months 6-12
Teething
Infants begin teething around 6 months and continue to do so until 2-3 years old.
- 20 primary teeth
Management consist of:
- Cold washcloth or teething ring; acetaminophen/ibuprofen for symptoms
- Dentist within 6 months of teething or before 1st birthday, whichever is first