Lect 6 - Infant Growth and Development Flashcards
Intra-uterine growth
Embryonic/fetal growth; assessed by birthweight
Gestational age
Age since 1st day of last menstrual period (post-menstrual age)
Full-term
38-42 weeks post-menstrual age
Low birthweight
<2500 g
What is assessed at delivery of the infant?
Measurement of length, weight, head circumference
- Assessed with growth charts
What are the cut-offs for intra-uterine growth patterns (SGA, AGA, and LGA)?
- SGA: <10th percentile
- AGA: 10-90th
- LGA: >90th
Infant factors leading to SGA
Congenital anomalies, genetic conditions, congenital infections
Placental factors leading to SGA
Small placenta, inadequate placental blood flow
Maternal factors leading to SGA
Smoking, alcohol, drugs, undernutrition
Risks associated by SGA
- hypoglycemia
- inability to maintain temp (not enough fat)
- decreased immune competence
- neurological and behavioural problems
(Related to in utero adaptations)
Infant and maternal factors leading to LGA
Infant: genetic
Maternal: uncontrolled diabetes
Risk factors are different for normal LGA and baby of diabetic mother
Risks associated with LGA
All: birth injury
Infants of diabetic mothers: hypoglycemia, hypocalcemia, respiratory, cardiac, cognetial problems
When do growth patterns require a follow up?
- flat growth line (not following growth curve)
- Sharp increase or decrease
- below 3rd percentile
- above 97th percentile (weight for length)
Corrected age for premature infants:
Current age - (40 - gestational age) = Corrected age
Assumes full term is 40 weeks
Physiological adaptation to post natal life
Gastrointestinal function
- GI formed before 3rd trimester and amniotic fluid is ingested in the 3rd trimester, preparing GI for nutr
- GI motility mostly developed
- Infants can digest breastmilk efficinetly (high disaccharidases, low pancreatic amylase for starch, slightly low fat digestion)
Glomerular filtration rates (birth, 1 year, 3 years)
Birth: 30%
1 year: 70%
3 years: 100%
In relation to adult levels
Renal solute load
Electrolytes and urea that need to be excreted. Requires more water.
Increased by high protein
Protective adaptations in post natal life
Mucosal barrier function. Includes protective mechanisms in infant gut:
- gastric barrier, proteolysis, peristalsis, factors in breastmilk
- mucosal coat and microvillus membrane
- antibodies (IgG, sIgA), other substances
Major metabolic change at birth
Loss of a constant supply of glucose. Glycogen and triglyceride synthesis begin in the 3rd trimester. Plasma glucose decreases at birth and insulin reduces, glucagon increases.
AGPAR score
Appearance: skin colour
Pulse: heart rate
Grimace: response to stimulation
Activity: flexion (activity and muscle tone)
Respiration: Respiratory effort
5 numbers are added together
- 8-10 is good
- 5-7 may require some breathing help
- 4 or less require immediate help
Does not determine long term health
Primitive reflexes (4)
Rooting: head turning towards stroked face
Sucking: reflexive, not voluntary
Moro: “startle” reflex - arms move outwards and then towards body
Head lag/step: head movement during pull to sit, stepping movement when held upright
What is needed for milk feeding and baby food?
Milk feed: grasp nipple, suck, swallow, breathe
Baby food: tongue movement to move food back, upright posture and head control
What is needed for self feeding?
Finger foods: grasp, hand to mouth, tongue movement to side, upright posture and head control
Cup drinking: hand and object to mouth, tilt head and cup backwards, control free flowing liquid
Developmental milestones (Birth, 4-6 mos, 6 mos)
Birth: grasp nipple, suck, swallow
4-6 mos: grasp objects, improved head control, some vocalization
6 mos: transfers objects from hand to hand, hand to mouth, sit with support, 1st teeth, expresses food preferences
Developmental milestones (7-8 mos, 9 mos, 12-15 mos)
7-8 mos: sit independently, more vocalization
9 mos: pincer grasp, cruising on furniture
12-15 mos: walking, words, 1st molars
