Euro-Growth references on increments in length, weight, and head and arm circumferences during the first 3 years of life. Euro-Growth Study Group

Background: Reliable assessment of growth performance of infants and young children requires reference data increments. Available increment references are based on data fitted to mathematical models, a process that diminishes variation in increment values. Methods: Fully longitudinal data from the multicenter Euro-Growth Study (21 study sites; n = 2145 children) were used to develop sex-specific percentiles for increments in length, weight, and head and mid-upper arm circumferences for selected intervals during the first 36 months of life. Increments (per unit of time) were calculated for 2-, 3- and 6-month intervals from birth to 12 months of age and for 6-month intervals from 12 to 36 months of age. Weight increments were also calculated for 1-month intervals from birth to 6 months of age. The influence of sex, mid-parental height, and study site was determined using analysis of covariance. Comparison with other references was accomplished using percentile values. Results: Mean and standard deviation values as well as selected percentiles (P; P3, P5, P10, P25, P50, P75, P90, P95, and P97) of increments are presented. Length increments of boys were higher than those of girls until 5 months of age but tended to be lower thereafter. Weight increments of boys were higher until 9 months of age. Sex, mid-parental height, and study site explained only between 2% and 13% of the variances of increments. Mean increments were comparable but P10 and P90 substantially differed from published data. Conclusions: The new Euro-Growth references for increments in length, weight, and head and mid-upper arm circumferences provide tools for health workers that should be useful in screening for adequacy of growth during the first 3 years of life.