Growth
Prof Dr Müjgan Alikaşifoğlu
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Why growth is important?
Which factors influence growth
Fetal and postnatal growth (height, weight)
Statistics used in describing growth
Assesment of physical growth
Techniques of physical measurements
Other indices of growth
Growth and Development
• The basic science of pediatrics is growth
and development.
• People dealing with children’s health
should be familiar with the normal patterns
and milestones so that they can recognize
overt deviations from the normal ranges as
early as possible, in order for underlying
disorders to be identified and given
appropriate attention.
Growth and Development
• Growth and development refers to the
process by which the fertilized ovum
eventually attains adult status.
• Growth principally implies changes in size
of the body as a whole or of its seperate
parts.
• Development principally involves changes
of function.
Growth and Development
• Growth is not determined solely by
genetics. Environment also plays an
importante role.
• Heigth, for example, is a function of a
child’s genetic endowment (biologic),
personal habits of eating (psychologic),
and access to nutrious food (social).
Fetal growth and development
• The most dramatic events in growth occur
before birth.
• During early prenatal development the pattern of
growth is largely dictated by the fetal genome,
but as body size increases the fetus become
constained by maternal and environmental
influences such as uterine bloodflow, maternal
size and maternal disease.
• Fetal growth involves a massive cell
hyperplasia while, postnatal growth involves
more cell hypertrophy than hyperplasia.
Fetal growth and development
• These differing patterns of growth have
different hormonal requirements; the major
growth promoting hormones in postnatal
life, GH and thyroxine, having little
apparent influence on human fetal growth.
• These hormones do not cross the placenta
in physiologically important quantities.
Fetal growth and development
• Placenta acts as an endocrine gland.
• One of the important function of placenta
is, to syntesizes the hormones such as
placental prolactin, eustrogen, progesteron
and chorionic gonodotrophin which
influence fetal growth and maintaining of
pregnancy.
Fetal growth
Embryonic period (0-8 wk):
• By the end of wk 8, as the embryonic
period closes; the average embryo weight
9 gr and has a crown-rump length of 5cm.
Fetal growth and development
Fetal period:
• From the 9th wk on somatic changes consist of
increases in cell number and size and structural
remodeling of several organ system.
• By 10 wk, the face is recognizably human.
• By 12 wk, the gender of the external genital
becomes clearly distinguishable
• During the 3rd trimester, weight triples and
length doubles as body stores of protein, fat, iron
and calcium increase.
Genetic, hormonal, and
environmental influences on fetal
growth
Genetic and fetal factor
• Race, gender
• Congenital anomalies
• Chromosomal disorders
• Fetal hormons (insulin, corticosteroids,
thyroid hormone, androgens)
• Growth factors (IGF I, IGF II, TGF-α)
Genetic, hormonal, and
environmental influences on fetal
growth
Maternal uterine environment
• Uterine and placental anatomy
• Utero-placental function
• Human placental lactogen
• Substrate fluxes and transfer
• Uterine blood flow
• Maternal systemic disease
Genetic, hormonal, and
environmental influences on fetal
growth
Macroenvironment
• Infectious agents (TORCH-S)
• Diet and nutrion
• Social and emotional stress
• Drug and smoking
• Teratogens and toxins
• Altitude and temperature
• Ionizing radiation
The first year of life
• At term human male is larger than the female, by
150 gr on average.
• The sex related difference in body weight
becomes apparent from 34 weeks gestation
• Birthweight shows considerable variation within
race, ethnic groups, and individual families, the
last being related to parental height and weight.
• A newborn weight may decrease 10 % below
birthweight in the 1st wk as a result of
excreation of excess extravascular fluid and
possible poor intake.
The first year of life
• Infants should regain or exceed
birthweight by 2 wk of age and should
grow at approximately 30g/day during the
1st mounth.
• Between 3 and 4 mo, the rate of weight
gain slows to approximately 20g/day.
• Weight gain in the first 6 mo= 150-200
gr/wk, at least 600 gr /mo
The first year of life
• Between 6-9 mo, 15 g/day
• Between 9-12 mo, 12g/day
• Weight gain in the second 6 mo= 100-150
gr/wk, at least 400 gr/mo
• The fullterm infant will generally double
birthweight by 5 mo and triple it by 1 year.
The first year of life
3-12 mo Weight= age (mo) + 9/ 2 kg
The first year of life
Lenght:
• The lenght of a normal infant increases
during the 1st year by 25-30 cm
• First two trimenon= 8 cm/three months
• Second two trimenon= 4 cm/ three months
The first year of life
An increase in subcutaneous tissue in the
early months of life reaches it peak at
about 9 mo.
The second year
• The growth rate slows further in the 2 nd
yr of life and appetite declines.
• An average child will gain about 2,5 kg in
weigth and about 12 cm in height
Preschool years
Between the ages of 2 and 5 yr, the
average child gains approximately 2 kg in
weigth and 7 cm in height per year
Middle childhood
• Growth during the period :3-3.5 kg and 56 cm per year.
• Growth of the midface and lower face
occurs gradually.
Middle childhood
Weight
• 1-6 yr: age (yr)x2+8
• 7-12 yr: age(yr)x7-5/2
Height
• 2-12 yr: age(yr)x6+77
Or
• 3-6 yr: age(yr)x5+80
• 6-11yr: age(yr)x5+84
Statistics used in describing
growth
• In everyday use the term normal is
synonymous with healthy.
• In a statistical sense, normal means that a
set of values generates a normal (bellshaped) distribution.
• This is the case with anthropometric
quantities such as height and weight.
Statistics used in describing
growth
• For a normally distributed measurement, a
histogram with the quantity (e.g. height, or
age) on the x-axis and the frequency (the
number of children of that height) on the yaxis generates a bell-shaped curve.
• In an ideal bell-shaped curve, the peak
corresponds the arhitmetic mean of the
sample, and to the median and the mode
as well.
Statistics used in describing
growth
• The median: is the value above and
belove which 50% of the observations lie
• The mode: is the value having the highest
number of observations
• The extend to which observed values
cluster near the means determines the
width of the bell and can be described
mathematically by the standard deviation
(SD).
Statistics used in describing
growth
• SD measures the degree of dispersion of
observed values as they deviate from the
mean value.
• In the ideal normal curve, a range of
values extending from 1 SD below the
mean to 1 SD above the mean includes
approximately 68% of the value
Statistics used in describing
growth
• A range encompasing ± 2 SD includes
95% of the values
• ± 3 SD encompases 99.7% of the values.
Relationship between SD and
normal range for normally
distributed quantities
Observation included in
normal range
Probability of a “normal”
measurement deviating from
mean by this amount
SD
±1
%
68.3
SD
≥1
%
16
±2
95.4
≥2
2.3
±3
99.7
≥3
0.13
• Example: If the population measured is
healthy boys and individual boy’s height
falls more than 2 SD belove the mean,
than the probability that this boy belongs
to the population of healthy boys is less
than 2.3 %
Statistics used in describing
growth
• A measurement that falls “outside the normal
range”- arbitarily defined as 2, or sometimes 3
SD on either side of the mean- is atypical, but
not necessarily indicative of illness.
• However, the further a measurement falls from
the mean, the greater the probability that it
represents not simply the normal variation, but
rather a different, potentially pathologic,
condition.
Statistics used in describing
growth
• Percentiles: Another way of relating an
individual to a group.
• The percentile is the percentage of
individuals in the group who have
achieved a certain measured quantity
(e.g., a height of 95 cm).
• 10 % of observations
fall below the 10th
percentile,
• 90 % below the 90th
percentile.
Statistics used in describing
growth
• For anthropometric data, the percentile
cutoffs can be calculated from the mean
and SD.
• The 5th percentile corresponds to – 1.65
SD
• The 10th percentile corresponds to – 1,3
SD
• The 25th percentile corresponds to -0,7
SD
In this figure shows how frequency distributions of
height at different ages relate to the percentile
lines on the growth curve.
• The above measures of dispersion are
commonly used to locate an individual
member of a population with respect to the
average member
• On the weight chart for
girls 0-36 mo of age.
• The 9 mo age line
intersects the 25th
percentile curve at about
8 kg (75% weigh more).
Similarly a 9 mo-old girl
wieghing more than 10.2
•+/- 10cm. kg is heavier than 95% of
her peers
• By definition, the 50th
percentile is the median It
is also termed the
standard value in the
sense that the standard
weight for a 9 mo girls is
about 8.5 kg
Assesment of physical growth
Three principal phases of growth is
childhood:
• Rapid and rapidly decelerating growth of
the first 3 years
• The steady and slowly decelerating growth
of mid-childhood
• The growth of adolescence
Assesment of physical growth
• The infancy component of growth appears to be
largely nutritionally determined.
• Childhood component; the earliest onset could
be recognized at 6 months of age.
• Until the age of 3 years growth is a combination
of the infancy and childhood components acting
additively
• The childhood component is mostly dependent
on growth hormon
• Pubertal component depends on synergism
between sex steroids and growth hormon
Assesment of physical growth
• Weight, weight velocity
• Height, height velocity
• Head circumference, velocity of the
increase in head circumference
• Body proportions
• Chest circumference
Assesment of physical growth
• The most powerful tool to growth assessment is
the growth chart.
Growth chart interpretation
• For infants, the measure of lineer growth is
length, taken by two examiners (one to position
the child) with the child supine on a measuring
board.
• For older children, the measure is stature, taken
with a child standing on a stadiometer.
• This technical difference results in children’s
appearing to shift down in length as they change
from the younger to the older chart.
Assesment of physical growth
• The data are presented in five standart
charts:
• Weigth for age
• Height (length and stature) for age
• Head circumference for age
• Weight for height
• BMI
Assesment of physical growth
• Measurements of weight, height and head
circumference at any given time will
indicate the status of a child with respect
to other children of the same age but only
sequential measurements will indicate the
quality of the process through which each
child is achieving his or her growth
potential.
Height velocity calculation
• Care should be taken in choosing the time
interval between height measurements used in a
velocity calculation.
• Time intervales of less than 6 mo will
exaggerate measurement errors and a whole
year velocity is more appropriate.
• A child with a height velocity below the 25th
centile consistently needs to be investigated.
Height velocity calculation
• The advantage of using velocity as a
criterion of normality is that it detects
abnormal growth regardless of stature
achieved.
Assesment of physical growth
Another way to describe extremes of
height is the height age, the age at which
the standard (median) height equals the
child’s present height.
• A 30-mo-old child
who is as tall as an
average 12 mo old
has a height age of
12 mo.
• The weight age is
defined analogously
Analyses of growth patterns
• Growth is a process rather than a static quality.
• An infant at the 5th percentile of weight for age may be
growing normally, may be failing to grow, or may be
recovering from growth failure, depending on the
trajectory of the growth curve.
• Typically, infants and children stay within one or two
growth channels.
• A normal exception commonly occurs during the 1st year
of life. For full term infants, size at birth reflects the
influence of the uterine environment
• Size at age 2 yr correlates with mean parental height,
reflecting the influence of genes.
Analyses of growth patterns
• Between birth and 18 mo, small infants
often shift percentiles upward toward their
parents’ mean percentile.
• Large neonates often shifts downward,
with decelerating growth beginning at 3-6
mo and ending as an infant achieves a
new growth channel at approximately 1318 mo.
Analyses of growth patterns
• For children with particularly tall or short
parents, there is a risk of overdiagnosing
growth disorders if parental height is not
taken into account or, conversely, of
underdiagnosing growth disorders if
parental height is accepted uncritically as
the explanation
Target Height
Prediction of target height
• For girls: (Father height- 13)+mother height/2
• For boys: (Mother height+13)+ father height/2
• This gives the range of adult height (+/- 10cm)
that would occur in 95% of the offspring of the
parents in question.
• It is of diagnostic importance if predicted adult
height falls below this target range.
Analyses of growth patterns
• The analysis of a growth patterns provides critical
information for the diagnosis of growth failure.
• There is no universally agreed-on criterion for growth
failure; most consider the diagnosis if a child’s weight is
below the 5th percentile or drops down more than two
major percentile lines.
• Weight-for-height below the 5th percentile remains the
single best growth chart indicator of acute undernutrition.
• Children, who have been chronically malnurished may
be short as well as thin, so that their weight-for-height
curves may appear relatively normal.
Techniques of physical
measurements
• Accurate measurement of weight and
length is of obvious importance. Scales
should be calibrated regularly.
• Height
• Supine measurement- length
• In the younger child who can not stand
less than 3 years of age.
Techniques of physical
measurements
Supine measurement- length
• One person ensures the head is correctly
positioned with the fixed upright
headboard.
• A movable upright footboard is brought
firmly against the heel.
• The feet should be flat against the
footboard
• The child is positioned
against a vertical surface
• Shoes and socks should be
removed
• The feet should be together
and flat on the ground with
the heels touching the
backboard or wall The legs
should be straight with the
buttocks and the scapulae
against the backboard (heels,
buttocks, upper part of the
back, occiput against the
vertical upright)
• The arms should hang
naturally at the sides.
• The lower margins of the
orbit should be in the
same horizontal plane as
the external auditory
meatus
• The headbord of the
apparatus should then be
placed carefully on the
head (the external
audotory meatus and the
lower border of the orbit
should be in a place
parallel with the floor)
Techniques of physical
measurements
• One point to remember for accurate
measuremets is the diurnal variation in height.
• As a consequence of gravity on the
intervertebral discs, the diurnal variation in
stature can be as much as 20 mm although the
average variation is about 7-8 mm.
• Diurnal variation in height can be overcome by
exerting firm but gentle pressure on the mastoid
processes during measurements to stretch the
spine.
Techniques of physical
measurements
Weight preferably in the nude or in
minimal underclothes
Techniques of physical
measurements
Chest circumference
• Measurement is made midinspiration at
the level of the xiphoid cartilage or
substernal notch. Measurement is made
with the child recumbent up to age 5 year
and standing thereafter
Other indices of growth
Body proportion
• Body proportions follow a sequence of regular
changes with development.
• The head and trunk are relatively large at birth,
with progressive lengthening of the limbs
throughout development, particularly during
puberty.
• Proportionality can be assesses by measuring
the lower body segment, defined as the length
from the symphysis pubis to the flor, and the
upper body segment, defined as the height
minus the lower body segment.
Other indices of growth Body
proportion
• The ratio of upper body segment divided
by lower body segment equals
approximately 1.7 at birth, 1.3 at 3 yr of
age, and 1.0 after 7 yr of age.
• Higher U/L ratios are characteristics of
short-limb dwarfizm or bone disorders
such as rickets.
Other indices of growth
Skeletal Maturation
• Ossification of the fetal skleton begins at about
5th mo. The distal femoral and proximal tibial
epiphyses are usually ossified in the normal
fullterm infant.
• A general index of growth status is given by the
bone age as determined from reuntgenograms.
• We need reference standards to calculate bone
age. The most commonly use reference
standards are those of Gruelich and Pyle, which
require radiographs of the left hand and wrist;
knee films are sometimes added for younger
infants.
Other indices of growth
Skeletal Maturation
• Since girls are more advanced than boys in
skletal development at all ages, seperate
standards are necessary.
Other indices of growth
Dental development
• Dental development includes
mineralization, eruption, and exfoliation.
• Initial mineralization begins as early as the
second trimester (mean age for central
incisors, 14wk) and continues through 3 yr
of age for the primary teeth and 25 yr of
age for the permanent teeth.
• Eruption begins with the central incisors
and progresses laterally
Other indices of growth
Dental development
• Exfoliation begins at about 6 yr of age and continues
through 12 yr of age.
• Eruption of the permanent teeth may follow exfoliation
immediately or may lag 4-5 mo. The timing of dental
development is poorly correlated with other processes of
growth and maturation.
• Delayed eruption is usually considered when there are
no teeth by approximately 13 mo of age.
Common causes:
• Hypothyroid
• Hypoparathyroid
• Familial
• Idiopatic (the most common)
Other indices of growth
Physiologic and structural growth
• Respiratory rate and pulse rate decrease
throughout childhood
• Blood pressure rises begining at 6 yr of age
• Development of the paranasal sinuses continues
throughout childhood.
• The ethmoids and sphenoid sinuses are present
from birth, the frontal sinuses first appear
radiologically around 6 yr of age.
Other indices of growth
Physiologic and structural growth
• Lymphoid tissues develop rapidly, reaching adult
size by 6 yr of age and continuing to hipertrophy
throughout childhood and early adolescence
before receding to adult size.
• Nutritional needs as well as a wide variety of
biochemical and hematologic values undergo
marked developmental changes. For example,
the alkalene phosphatase level increases during
periods of rapid bone growth.