Arm and head measurements in the newborn.

A total of 6,696 newborn infants were evaluated to investigate the trend in, and suggest the optimal time for assessment of, head circumference and mid-arm circumference (MAC) measurements. The measurements were recorded on the first, 3rd, 5th and 7th days of life and the mean values compared for significant differences. There were no significant differences between the mean values of head circumference and MAC for any two days of assessment compared. There was also no particular trend in the observed measurement during the first week of life. To guarantee prompt and appropriate management of high-risk infants, determination of these measurements at birth, and during the first 24 hours, is suggested as optimal.