Growth velocity curves: What they are and how to use them

Abstract

Growth velocity charts are important to evaluate the growth of a subject and are available for height and weight, in both boys and girls. Height or weight velocity is a variable derived from the measurement of height or weight at different times and represents the increase in height or weight during a fixed period. Height or weight velocity charts depict the age-dependent changes in velocity that characterize human postnatal growth. Height velocity (HV) is characterized by rapid progress from birth up to the end of the first year of life, followed by decreases through the second year. The male neonate grows slightly faster than the female, but the velocities equilibrate at 7 months of age. Then, up to adolescence there are no significant differences in growth rates. The adolescent height spurt in females begins at 10.5 years and reaches a peak at about 12 years. Males instead exhibit the pubertal spurt later at 12.5 years and reach a peak HV at 14 years. The curves for weight velocity (WV) show a peak before the first year of age for both boys and girls. The male WV is greater at birth, but reaches an equilibrium with female WV at about 8 months and then gradually lags behind the female WV until adolescence. During pubertal development WV peaks at about 12.9 years in girls and 14.3 years in boys; peak WV generally occurs at a slightly older age than peak HV. Growth velocity is central to the diagnosis of growth retardation. In the presence of a very low single value for HV (3rd centile), the paediatrician should start a prompt endocrinological evaluation. When height is >3rd centile and more than one HV value is available, an endocrinological evaluation is warranted when the values are persistently under the 25th centile. An HV value consistently above the 75th centile should be checked and correlated to signs of precocious puberty and elevated body weight. In conclusion, growth velocity charts are valuable tools for the paediatrician and can be used by clinicians in the screening and assessment of metabolic/endocrinological disorders.