Standard curves for mid arm circumference and mid-arm/head circumference ratio in newborns.

One Thousand singleton neonates, between 28 and 44 weeks of estimated gestational age (EGA) were measured within 48 hours of their birth for upper mid-arm circumference (MAC), head circumference (HC) and birth weight (BW). Regression analysis was used to draw standard curves for MAC versus EGA and mid-arm circumference/head circumference ratio (MAC/HC) versus EGA. Correlation coefficients were 0.961 for MAC versus EGA and 0.889 for MAC/HC versus EGA (p less than 0.001). MAC, MAC/HC and HC were also highly correlated with birth weight (p less than 0.001). These standard curves make available a discriminating method for evaluation of intra-uterine growth and a non-invasive technique for following somatic protein status in growing preterm infants.