Statural growth, a fundamental characteristic of childhood, is a complex process that is determined by the interaction of genetics, nutrition, and socioeconomic factors . Regular assessment of growth is an essential part of pediatric practice and includes comparison of a child's growth pattern to established norms. When determining the normality of a child’s growth pattern, serial measurements of height and calculation of height velocity (HV) is more useful than a single height-for-age percentile . In interpreting a child's HV, allowance must be made for age, pubertal development, and other factors.
The causes, diagnosis, and treatment of children with abnormally rapid growth and tall stature will be reviewed here. The evaluation of children with short stature is discussed elsewhere. (See "Causes of short stature" and "Diagnostic approach to children and adolescents with short stature".)
In both boys and girls, the maximum velocity for linear growth occurs during the fourth month of intrauterine life, reaching 2.5 cm/week , followed by a slowing until birth. Size at birth is determined more by maternal nutrition and intrauterine and placental factors than by genetics; the genetic factors that influence growth are not fully expressed during fetal growth. As a result, the correlation coefficient between birth length and adult height is only 0.25 .
During the first two years of life (infantile phase), linear growth initially is very rapid and gradually decelerates. Overall growth during this period is about 30 to 35 cm. During this period, an infant’s height curve often crosses percentile lines as the growth moves away from the influences of the intrauterine environment and toward the child’s genetic potential. (See "Normal growth patterns in infants and prepubertal children", section on 'Linear growth'.)
The childhood phase of growth (ages two years to puberty) is characterized by a relatively constant height velocity (HV). Most children grow at the following rates (representing the 10th to 90th percentiles):