Doctors have long recognized the value of evaluating babies' and children's
growth and
comparing it with that of other kids in the same age group. By doing so, they
can track a child's growth over time and monitor his development in relation to
both other children and himself. The growth charts your pediatrician uses for
this purpose are a standard part of any well-child checkup.
This article will help you become familiar with these charts. As you learn
more about them, you will discover what an important tool they are.
What Are Growth Charts? Doctors use growth
charts to compare a child's measurements with those of other children his age.
This helps the doctors determine whether a child's growth is adequate. Boys and
girls are plotted on different charts because their growth rates and patterns
differ. For both boys and girls there are two sets of standard charts: one for
infants ages 0 to 36 months and another for children ages 2 to 18 years. The
charts are a series of percentile curves that show the distribution of growth
measurements of children from across the country.
The growth charts most commonly used in the United States were developed by
the National Center for Health Statistics and were first released in 1977.
Recently, the center revised the charts to update their data and reflect greater
cultural and racial diversity. (The original infant charts were based on data
from one study of mainly middle-class, formula-fed Caucasian infants from
southwestern Ohio - not a very inclusive population sample. The data for
the older children's charts were collected in national health surveys from 1963
to 1974). Also, these new charts go up to age 20.
Looking at the Charts The new charts represent
the most recently published (June 2000) standards for U.S. children. By plotting
your child's measurements on these charts, doctors are able to compare your
child's growth patterns with data collected on thousands of U.S. children.
Remember that only those measurements that are obtained in your child's doctor's
office or taken by another properly skilled person should be plotted. Home
measurements are frequently inaccurate and can lead to faulty data.
The commonly used standard growth charts include:
For children ages birth to 36 months (3 years): Girls' length and
weight for age Boys'
length and weight for age Girls'
head circumference for age and weight for length Boys' head
circumference for age and weight for length
For children ages 2 to 20 years: Girls' stature
(height) and weight for age Boys' stature
(height) and weight for age Girls'
weight for stature (height) Boys'
weight for stature (height)
At the Doctor's Office During regular
well-child visits, your child's doctor will record certain measurements in your
child's medical record. With an older child, a doctor may plot four numbers on
the growth charts: height for age, weight for age, weight for height, and, a
recent addition, body mass index (BMI). An infant usually is measured for
length for age (because kids usually can't cooperate for an accurate
standing-height measurement until about age 2 to 3 years), weight for age,
weight for length, and head circumference for age.
Length or height for age is simply a child's height at that particular age.
The same is true of weight for age. Weight for height (or length) compares
someone's weight at his height to other children's weight at that same height
(or length). Although weight for height charts can be useful for assessing body
fatness in children 2 years and older, the Centers for Disease Control and
Prevention have stressed that the recently released body mass index charts
are preferred for this purpose. Body mass index is calculated from both weight
and height and in most cases is a fairly good indicator of a child's amount of
body fat. Head circumference measures the distance around an infant's head at
the widest point.
Doctors take these measurements for premature infants, too.
They correct for prematurity on the growth charts until age 2 years by
subtracting the missed months of gestational time from the child's chronological
age - so an 8-month-old baby who was born two months early will be plotted
as a 6-month-old. That reflects the fact that a premature 8-month-old has been
growing for two fewer months than an 8-month-old who was born on time. (By the
time they are 2 years old, premature kids usually catch up to other children in
growth).
|