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Growth and Development. Intrauterine growth and nutrient accretion Body Composition Growth Assessment Growth Charts Patterns Alterations in Growth Development Metabolic Physiologic neurologic. Growth. Growth.

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growth and development
Growth and Development

Intrauterine growth and nutrient accretion

Body Composition

Growth Assessment

Growth Charts

Patterns

Alterations in Growth

Development

Metabolic

Physiologic

neurologic

growth3
Growth

A normal, healthy child grows at a genetically predetermined rate that can be compromised by imbalanced nutrient intake

growth4
Growth

Growth is a dynamic process defined as an increase in the physical size of the body as a whole or any of its parts associated with increase in cell number and/or cell size

Reflects changes in absolute size, mass, body composition

undernutrition
Undernutrition

⇩⇩ weight⇒⇒⇩length or height

Underweight ⇒⇒ proportionate

fetal growth from 25 40 weeks ga
Fetal Growth from 25-40 weeks GA
  • Weight increases 4-fold
  • Length and OFC increase 2-fold
body composition
Body Composition
  • Fat accounts for 0.5% of body weight at the fifth month of fetal growth and 16% at term.
  • 3rd trimester: increase from 1-3% of body weight to 10-16% of body weight at term
minerals
Minerals
  • Two-thirds of mineral content of full-term newborn is accummulated in the last trimester of pregnancy.
determinants of fetal growth
Determinants of fetal growth
  • Genetics
    • Maternal/paternal genes, race, sex estimated to account for 20% of variance in birth weight
  • Environmental factors
environmental factors
Maternal health

Nutrition

Glucose, fatty acids, amino acids for tissue deposition and fuel for oxidative purposes

Ability of maternal-placental system to transfer nutrients to fetus

Endocrine environment

E.g. LGA infant: glucose-insulin-growth factors

Environmental factors
individual growth patterns
Individual Growth Patterns
  • Weight and length at term appear to be primarily determined by nongenetic maternal factors
  • Birth weigh and birth length weakly correlate with subsequent weight and length values
individual growth patterns cont
Individual Growth Patterns, cont.
  • African American males and females are smaller than whites at birth, but they grow more rapidly during the first 2 years
  • Patterns of growth in breastfed infants are different from formula fed infants
growth in first 12 months
GROWTH IN FIRST 12 MONTHS
  • From birth to 1 year of age, normal human infants triple their weight and increase their length by 50%.
  • Growth in the first 4 months of life is the fastest of the whole lifespan - birthweight usually doubles by 4 months
  • 4-8 months is a time of transition to slower growth
  • By 8 months growth patterns more like those of 2 year old than those of newborn.
body composition16
Body Composition
  • BMI and percentage of body weight made up of fat increase rapidly during the first months of life
    • After birth, fat accumulates rapidly until approximately 9 months of age
weight gain of breast fed vs bottle fed infants 8 112 days of age g d
Weight gain of Breast fed vs bottle fedinfants: 8-112 days of age (g/d)

Nelson et al Early Human Development 19:223 1989

slide20
Rates of gain for breastfed and formula fed infants during early months of life generally have been found to be similar although some reports have demonstrated greater gains by breastfed infants and others have shown greater gains by formula fed infants
assessment
Assessment
  • Screening identifies nutritional risk and/or need for further assessment.
    • Underweight
    • Overweight
    • Failure to grow
    • “over fat”
reference vs standard
Reference vs Standard
  • Reference: a set of data used for normalizing measurements so that they can be manipulated statistically, grouped and compared with other sets of measurements. In principle, implies no value judgement and tells us nothing about optimal or satisfactory growth
  • Standard: Implies a value judgement. In theory, standards are selected based on representing “optimal”, “normal” or “goal”
fetal neonatal growth charts
Fetal/Neonatal Growth Charts
  • Intrauterine charts
    • Classification of newborn
      • AGA
      • LGA
      • SGA
  • Postnatal Charts
intrauterine fetal growth standards
Intrauterine/Fetal Growth Standards
  • Lubchenco
  • Gairdner
  • Babson Benda
  • Fenton
  • Olsen
fenton chart
Fenton Chart

Data Sets:

Kramer et al: 676,605 infants 22-43 weeks

Nicholson et al : 376,000 Swedish infants 28-40 weeks

Breeby et al: OFC (N=29090) and Length (N=26,973) 22-40 weeks

CDC Data

Time period 1963-2001

postnatal growth charts
Postnatal Growth Charts

Accounts for initial weight loss

Dancis: Data 1948, very small sample size in lowest weight group

Ehrenkranz: Pediatrics 1999:104:280

N=1660

14-16 g/kg/d weight gain

0.9 cm/week increase length

0.35 cm/week increase OFC

infant growth references

Infant Growth References

A variety of growth references were developed and and used in the U.S. since the early 1900’s

growth references timeline
Stuart/Meredith Growth Charts (1946-76)

Caucasian, Boston/Iowa city, small sample size

NCHS growth charts (1976-1978)

Cross sectional Data from NHES, NHANES, and FELs

CDC produced normalized version

1978 WHO recommended international use

CDC (2000)

5 cross sectional nationally representative surveys between 1963-1995

Included more breast fed infants

WHO (2006)

Data from Brazil, Ghana, India, Norway, Oman and USA

Multiethnic, affluent

Exclusive breastfeeding to 4 months

Solids according to recommendations 6 months

Continued breastfeeding to 12 months

Growth references: timeline
growth charts
Growth Charts
  • CDC/NCHS
    • http://www.cdc.gov/growthcharts/
  • World Health Organization
    • http://www.who.int/childgrowth/en
nchs growth charts concerns
NCHS growth charts: Concerns
  • Infant data: Fels study
    • Primarily formula fed
    • Underrepresented groups: largely caucasian, middle class
    • Intervals of measurements (q3 months from 3-36 months) may not define dynamic patterns during rapid growth phases
    • Statistical smoothing proceedures
cdc growth charts compared to older nchs
CDC Growth Charts (compared to older NCHS
  • Standardized data collection methods
  • Expanded sample
  • More breastfed infants
  • Exclusions
    • VLBW infants
    • NHANES III weight data for >6 year olds
cdc nchs growth charts
CDC/NCHS Growth Charts
  • Clinical charts for infancy for girls and boys:
    • weight
    • length
    • weight for length
    • OFC
  • Choice between outer limits at 3rd and 97th or 5th and 95th percentiles
who child growth standards
WHO Child Growth Standards
  • Released new growth standards April 2006
    • Assumed that infants and children between birth and 5 years grow similarly when needs are met.
  • Concerns for CDC charts included:
    • Frequency of growth measures during dynamic periods of infant growth
    • Statistical methods
slide36

Standard vs Reference

  • Released new growth standards April 2006
    • Assumed infants and children grow similarly when needs are met.
  • Concerns for CDC charts included:
    • Frequency of growth measures during dynamic periods of infant growth
who growth charts
WHO growth charts
  • Full term low birthweight infants not excluded
  • Birth to 2 years
    • N 1743 ----- 882
  • 2-5 years
    • N 6669
who v s cdc
WHO v.s. CDC
  • Infancy
    • WHO mean > CDC mean birth-6 months
    • “healthy breastfed infants track weight/age along WHO but falter on CDC”
    • Cross at 6 months and WHO mean < 6months
who v s cdc43
WHO v.s. CDC
  • CDC
    • Heavier, shorter
  • WHO
    • taller
  • WHO
    • Higher estimates of overweight
    • Lower estimates of underweight, undernutrition
cdc recommends use of who growth standard
CDC Recommends use of WHO growth standard
  • 2006 convened expert panel of NIH and AAP to review scientific evidence and use of WHO growth charts in clinical US settting
  • September 2010 recommended use of WHO charts for infants birth to 2 years
cdc recommendations for infant growth charts
CDC Recommendations for infant growth charts
  • http://www.cdc.gov/growthcharts
  • Use WHO charts from birth-24 months
  • CDC charts for > 24 months
  • As a screen, 3rd and 97th percentile on WHO corresponds to 5th-95th on CDC
  • Clinicians should be aware that fewer individuals will be screened as “underweight” and more as “overweight” using WHO
controversies issues
Controversies/Issues
  • Screen vs assessment
  • Standard vs reference
  • Typical vs ideal growth
  • Environmental influence
  • Variety of diets may result in acceptable growth and nutrition status
  • Normal population divesity
  • Plot individuals on both CDC and WHO. Does your assement change? Absolute size vs pattern
alterations in growth
Alterations in Growth
  • SGA
  • LGA
  • Preterm birth
  • Failure to grow (FTG)
sga infant
SGA Infant
  • < 10th percentile
    • Symmetric vs asymmetric
  • Not a part of natural diversity or genetically determined
  • Placental insufficiency limiting nutrient supply to fetus
sga infant51
Etiology

Programing

Timing

Body Composition

Cell number

Cell size

LBM vs. adiposity

BMC

Increased BMR

Impaired gluconeogenesis

Risk for hypoglycemia

Risk for iron deficiency anemia

Risk for adult onset diseases

SGA Infant
lga infant
LGA Infant
  • > 90th percentile
  • Not part of natural diversity or genetically determined
  • Macrosomic, increased adiposity vs proportionate
extra uterine growth restriction
Extra uterine Growth Restriction

Extra uterine growth restriction refers to the development of severe nutrient deficits in premature infants during hospitalization

extra uterine growth restriction remains a serious problem in prematurely born neonates
Extra uterine Growth restriction Remains a Serious Problem in Prematurely Born Neonates

Cooke et al Arch Dis Childhood 2004:89:428-430

N= 659 from 4 level III and 10 level I-II units

Variable but universal incidence of postnatal growth retardation (PGR) comparing level III and level I-II units

PGR in level III associated with birth weight, birth weight Z score, and GA

45% of PGR in level III unit unexplained (? Variability in nutritional practices)

? PGR in level I-II vs. level III

extra uterine growth restriction remains a serious problem in prematurely born neonates56
Extra uterine Growth restriction Remains a Serious Problem in Prematurely Born Neonates

Clark: Pediatr 2003

N=24,371 from 124 NICUs 1997-2000

Estimated based on growth <10th percentile at discharge

Estimates:

Wt: 28%

Lngth: 34%

OFC: 16%

extra uterine growth restriction57
Extra uterine Growth Restriction
  • NICHD Neonatal morbidity Research network
    • 16% ELBW infants are SGA at birth
    • At 36 weeks CA 89% demonstrate growth failure
    • Follow up at 18-22 months show 40% with weight, length, OFC <10%
in utero
In utero

Fetal GI tract is exposed to constant passage of fluid that contains a range of physiologically active factors:

growth factors

hormones

enzymes

immunoglobulins

These play a role in mucosal differentiation and GI development as well as development of swallowing and intestinal motility

at birth
At Birth

Gut of the newborn is faced with the formidable task of passing, digesting, and absorbing large quantities of intermittent boluses of milk

Comparable feeds per body weight for adults would be 15 to 20 L

gastrointestinal maturation
Gastrointestinal Maturation

Reference

Josef Neu, Gastrointestinal Maturation and implications for infant feeding, Early Human Development 2007 83 (767-775)

Neonatal Gastroenterology, Clinics in Perinatology June 1996 23:2

Weaver and Lucas Development of Gastrointestinal Structure and Function, Chapter 3 in Neonatal Nutrition and Metabolism ed Hay Mosby 1991

Nutrition and Metabolism of the Micropremie in Clinics in Perinatology March 2000n 27:1

gastrointestinal maturation62
Gastrointestinal Maturation

Intestinal length increase 1000X from 5-40 weeks, doubles in the last 15 weeks.

Villi formed at 16 weeks

Fetus begins to swallow around 16 weeks by 2nd trimester is swallowing as frequently as every 45 minutes. By term, the fetus ingests approximately 300 ml/d

slide64

Maternal-fetal-placenta

    • Interaction
    • Individual metabolism
  • Glucose, amino acids, and fatty acids primary nutrients for tissue deposition and oxidative fuel
  • Hormonal regulation
    • Not well understood
    • Main hormones are placentally produced
    • Insulin like growth factors induce cell proliferation and DNA, increase glucose and amino acid uptake, and inhibit protein breakdown
    • Placental growth hormone stimulates IGF and is reduced in IUGR
    • ? Leptin. Associated with fetal weight, fetal BMI, and fetal fat mass
carbohydrate metabolism
Carbohydrate Metabolism

Fetus

Glucose and lactate

Glucose from maternal circulation via facilitated diffusion

At birth, plasma glucose concentration about 2/3 maternal

Used for oxidative fuel and source of carbon for glycogen and other organic compounds

Understress fetus can produce glucose with gluconeogenic enzymes present at 10 weeks (but primarily maintained by maternal supply

hi

cho lactase
CHO: Lactase
  • Lactase activity is highest in infancy (term)
  • Term Infants
    • Lactase 30% of adult. Stimulated with first feeds
  • Preterm infants:
    • Lactase levels remain low <36 weeks
    • 30-40% NB levels
    • Breath hydrogen tests confirm inefficient digestion of lactose
cho glucoamylase
CHO: Glucoamylase
  • Primarily responsible for starce digestion in youn infants (<3 months)
  • Glucoamylase activity increases during 3rd trimester
  • Adult levels reached by 12 months
cho pancreatic amylase
CHO: Pancreatic Amylase
  • Pancreatic Amylase primarily responsible for complex starch digestion
  • Pancreatic amylase begins to increase after birth but may take up to 3 months before significant rise
  • Adult levels may not be reached until after 12 months of age
slide70
CHO
  • At birth
    • Catoecholamines, thyroxin, and glucagon increase and falling glucose levels stimulate glu-6-phosphatase
    • Glycogenolysis and hepatic glucose output are thus stimulated
protein
Protein

Source of amino acids for protein synthesis

Release of bioactive peptides that contribute to regulation of many physiologic functions including metabolism, immunity, blood pressure, GI function, and food intake (eg CCK, GLP-1, glucagon, insulin)

protein metabolism
Protein Metabolism

Fetus requires protein for protein synthesis and the provision of energy

Maternal-fetal amino acid transfer is a complex process involving several sodium dependent transfer proteins. Intracellular and extracellular sodium gradient provides driving force

Fetal amino acid profile differs from neonate

protein73
Protein

Elevated levels of amino acids and products of protein metabolism may exceed renal and hepatic capacity to excrete excess nitrogen with resulting acidosis, hyperammonemia, elevated BUN, diarhea.

Potential consequences: neurodevelopmental, stimulation of insulin and IGF-1, which can enhance growth, adipogenic activity and may be linked to later obesity

protein74
Protein

Digested in upper intestine via pancreatic proteases. Most of the brush border and cytosolic peptidases are well developed in the preterm infant and peptide transport system is efficient.

Macromolucules can be actively taken up by pinocytosis and preterm infants have demonstrated to capability to absorb lactoferrin. Preterm infants have increased intestinal permeability

slide75
Whey proteins induce fast but transient increase in plasma amino acids. Concentrations peak at 1-2 hours and return to baseline after 3-4 hours
  • Casein proteins are associated with slow gastric emptying, a slower and reduced rise in plasma amino acids and inhibit whole body protein breakdown
lipid metabolism
Lipid Metabolism

Fetus

Fetus requires large amounts of lipids particularly within developing nervous system (DHA, ARA)

Fetus acquires lipid via maternal placental transfer and capable of synthesizing cholesterol and fatty acids

Transfer impacted by maternal FA profile

Dependent on maternal supply for EFA

preterm
Preterm
  • Bile acids and lipases limited
    • Approx 30% newborn levels 24-36 weeks
renal
Renal

Limited ability to concentrate urine in first year due to immaturities of nephron and pituitary

Potential Renal solute load determined by nitrogenous end products of protein metabolism, sodium, potassium, phosphorus, and chloride.

ur ine concentrations
Urine Concentrations

Most normal adults are able to achieve urine concentrations of 1300 to 1400 mOsm/l

Healthy newborns may be able to concentrate to 900-1100 mOsm/l, but isotonic urine of 280-310 mOsm/l is the goal

In most cases this is not a concern, but may become one if infant has fever, high environmental temperatures, or diarrhea

postnatal acquisition of intestinal microbiome
Postnatal Acquisition of Intestinal Microbiome
  • Following birth the sterile newborn GI tract colonized by environmental microorganisms
  • State of mutualism (microbiome) role in health, growth, development.
postnatal acquisition of intestinal microbiome82
Postnatal Acquisition of Intestinal Microbiome
  • Systemic and mucosal immune fx of NB differs from adult
  • Fetal immune system evolved to avoid maternal rejection vs process pathogens
microbiome
Microbiome
  • NB must undergo extensive postnatal development of which the acquisition of GI microbiome is major determinant of early immune system
  • Role of breastmilk: establishment of symbiotic core microbiome
development of infant feeding skills
Development of Infant Feeding Skills
  • Birth
    • tongue is disproportionately large in comparison with the lower jaw: fills the oral cavity
    • lower jaw is moved back relative to the upper jaw, which protrudes over the lower by approximately 2 mm.
    • tongue tip lies between the upper and lower jaws.
    • "fat pad" in each of the cheeks: serves as prop for the muscles in the cheek, maintaining rigidity of the cheeks during suckling.
    • feeding pattern described as “suckling”
developmental changes
Developmental Changes
  • Oral cavity enlarges and tongue fills up less
  • Tongue grows differentially at the tip and attains motility in the larger oral cavity.
  • Elongated tongue can be protruded to receive and pass solids between the gum pads and erupting teeth for mastication.
  • Mature feeding is characterized by separate movements of the lip, tongue, and gum pads or teeth
development86
Development
  • Neurophysiologic
    • Homeostasis
    • Attachment
    • Separation and individuation
  • Oral Motor
stages of development
Stages of Development
  • Homeostasis
  • Attachment
  • Separation and individuation
slide90
Infant feeding and Growth
    • Goals
    • Expectations
    • Considerations