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).

Go to next page

Printer-friendly version Email this article to a friend Send email to us

Jump to another section of this article Growth Charts What Do the Percentiles Mean? and What Can the Charts Tell Me About My Child's Growth? Reviewer name and date on last page