Many of you
have probably watched your baby or child weighted and measured
including head size taken. The nurse or doctor plots these numbers
on a chart or graph, and tell you where your child falls. You
then wonder, what does the 5th percentile, or 50th percentile
mean? Mainly, the big question is: "Is my child's growth
OK?" "Is he/she growing OK." I would like to take
a few moments and try to explain a little more about what the
charts mean, and most important a few guide lines as to what is
OK or not OK for your child. The term growth chart refers to a
graph used to plot either height, weight, or head circumference
(till 2 or 3 years old); against, age in months or years. There
are different charts for boys and girls, and usually they are
divided in age groups from birth to 36 months and 2 to 18 years.
The "percentile" lines on these charts indicate the
number of "normal" children expected to fall above and
below your child's actual measurement. For instance, if your child
is at the 50th percentile for weight, that says 50% (1/2) of all
children your child's age will be heavier, and 50% (1/2) will
be lighter. If your child's height is at the 75th percentile,
that says 25% (1/4) of children will be taller, but 75% (3/4)
will be shorter. The interpretation of these charts can be misread
with many errors. Therefore, you must interpret and understand
these numbers and percentiles relative to your child's growth,
and always remember, no single number is as important as what
happens and changes over time. Ideally, your child's height and
weight (and for infants head size) will be the same percentiles.
However, the current trend is to weigh, one percentile line below
the height line. Many of the standard growth curves are based
on general values gathered over 20-30 years ago, and nowadays,
the goal is to be a little "leaner."
As noted above,
no absolute value or percentile line is as important as changes
over time, which is one of the reasons regular check-ups and plotting
of height and weight, etc. can help detect potential problems
early, and often when they are more easily correctable. As a physician,
a child's growth chart is a major guide in differentiating normal
from abnormal variations. Growth, is the central characteristic
of normal children and deviations from the child's norm provide
an early warning of pathologic processes. Deviations from a child's
norm usually indicate some internal defect or environmental insult.
In general, children with measurements either above the 97th or
below the 3rd percentile require further evaluation, as do children
whose height and weight differ by more than two percentile lines
answer to the question "Is my child eating enough or too
much?" is to look at the growth chart. A child can be "poor"
eater and be overweight, or a great eater and be underweight.
A child who is "underweight" but following his or her
growth line is probably doing fine, whereas a child who was "light"
but is now "falling off" the growth chart, may be in
trouble. Likewise positions
on the height curve, and in an infant head size, must be interpreted
in the same relative ways.
always maintain a regular check-up schedule for your child, and
if you are wondering how he or she is growing, ask to see the