Evidence of growth retardation in neonates of apparently normal weight.

The aim of this study was to examine the relationship of ponderal index (PI) and the ratio of mid-arm circumference to occipito-frontal circumference (MAC/OFC) to the delivered weight of the child. Measurements were made on 160 singleton neonates with birthweight greater than 2500 g and delivery at 37 weeks or more. Surprisingly, there was a highly significant correlation between PI and birthweight and MAC/OFC and birthweight. We conclude that: (1) values of PI must be evaluated in relation to birthweight, and not against a single absolute standard for the whole normal population; (2) measurement of PI and MAC/OFC may reveal a group of growth-retarded infants amongst infants of apparently 'normal' birthweight; and (3) this group of infants might be a target for the extra care normally accorded to the low birthweight infant.