A growth chart is used to measure and compare a child's growth to a standard range. The nationally accepted growth charts are based on measurement data collected by the National Center for Health Statistics. The parameters which are measured include height, weight and head circumference.

Height and weight measurements are used to document a child's height or length (in inches or centimeters), weight (in ounces and pounds, or grams and kilograms), based on his age in weeks, months, and years. The 'height' of children under 3 years is measured while they are lying down. The height of children 3 and over is measured while they are standing. Height and weight measurements are recorded and graphed up through 17 years of age.

Head circumference is a measurement of the size of the head taken by wrapping a tape measure above the eyebrows and around to the back of head.

Measurements are compared to the "standard" or normal range for children of the same gender and age. Results are read as percentiles of average. For example, a child with a height at the 75th percentile means that only about 25% of children his age and gender are taller and about 75% of children are shorter.

Growth charts are important in that they may provide an early warning that the child has a medical problem. For instance, during the first 18 months of life and particularly during early infancy abnormal growth of the head circumference can alert the physician to a pending problem. Growth that is too rapid may indicate the presence of hydrocephalus (water around the brain), a brain tumor or other conditions that cause macrocephaly (abnormally large head). Growth that is too slow may indicate problems in brain development, early fusion of sutures (the bones of the skull), or other problems.

Insufficient gain in weight, height or a combination may indicate failure-to-thrive, chronic illness, neglect, or other problems.

Abnormal growth as seen on the growth charts is only an indicator of a potential problem. Your doctor will determine if it represents an actual medical problem or simply needs to be followed carefully.