Please read this brief explanation of
growth charts before viewing them at the bottom of this page.The
birth of a new baby is greeted by many questions from parents, relatives and friends.
"Is the baby okay?" "Does the baby have all its fingers and toes?" The
next most common questions are about the infant’s size - "how much did the baby
weigh and what is the length?" These important values are then carefully recorded in
the infant’s "baby book," written on birth announcements, and given out to
grandparents, relatives and friends.
Parents really have the right idea here. These measurements will become a good
indicator of the baby’s overall health, especially during the first three years.
Physicians too are well aware of this close relationship. Infants who are well nourished
nutritionally, receive emotional bonding from their parents, and have not developed a
chronic medical problem will grow following a regular pattern.
Pediatricians and family physicians use a growth chart to keep track of a child’s
progress. As all of us realize, there is a wide variation in the height and weight of
"normal" children. Growth charts were developed from information obtained by
measuring and weighing thousands of children. From these numbers the national average for
weight and height for each age and sex were established and plotted forming a curved line.
This became the 50th percentile curve, meaning in a sample of 1,000 boys or
girls, 500 would be above the curve and 500 would be below. Then other curves were
established representing the 10th, 25th, 75th, and 90th
percentiles. By definition, 100 out of one thousand normal children will be at the 10th
percentile. Another way of looking at it is that a child whose height fell on the 10th
percentile would be taller than 100 and shorter than 900 children of the same age and sex.
Four separate charts are published by the National Center for Health Statistics: boys,
birth to 36 months and 3 to 18 years of age, and girls, birth to 36 months, and 3 to 18
years of age. Growth charts are adjusted for babies born prematurely and babies who are
small-for-dates at birth.
Parents often focus their attention on where a child’s growth is plotted on the
chart. This may be particularly concerning to a parent if the measurement falls below the
50th percentile. Does this mean that their daughter will not make the
dean’s list or their son will be too short to play basketball? Absolutely not! As
long as the child is consistently in the normal range (between the 10th and 90th
percentile) and stays in that range on multiple well child visits, everything is fine.
Physicians become concerned when the child repeatedly falls below the lower limits
for weight or height, or above the upper limits for weight. What is important is that
the child gets on a steady percentile line and stays there.
For example, a physician might worry if at a six-month-old baby was in the 75th
percentile and at nine months was in the 25th percentile and then at 16 months
was below the 10th percentile.
Another measurement performed during well checkups is the head circumference. Like
height and weight, head circumference is carefully recorded and plotted on its own chart.
Pediatricians become concerned when the head is growing too slowly or too quickly on
repeated measurements. This measurement is also adjusted for babies born prematurely.
It is important to emphasize again that parents not focus their attention on an
isolated entry in their youngster’s growth chart. Measurement errors do occur -
the squirming infant on a baby scale may be difficult to weigh, a toddler recovering from
a bout of diarrhea may seem to have dropped weight percentiles, or the slouching
adolescent being measured during a sports physical. The growth trends over successive
visits are more accurate and provide parents and physicians with important information
about a child’s health.
