Head growth and IQ were correlated at ages 2, 5 and 8 years in children grouped according to birth weight in the Departments of Obstetrics and Gynecology and Pediatrics, University of Melbourne, Australia, and the Royal Women’s Hospital, Melbourne. All children were white and with no signs of moderate or severe cerebral palsy. Using the National Center for Health Statistics reference values more group 1 children (birth weight 500-999 g) than group 2 children (birth weight 1,000-1,499 g) were below the 10th percentile at ages 2 and 8 years. Using the Nellhaus standards the difference between groups 1 and 2 was not significant and head growth appeared to be satisfactory at age 2 years. Comparing group 3 (birth weight greater than 2,500 g) with groups 1 and 2 combined, fewer of the group 3 children were below the 10th percentile at both ages 2 and 8 years using the NCHS reference and at age 8 years using the Nellhaus data. The heads of very low birth weight children were progressively narrower but not longer than those of normal birth weight children. Dolichocephaly was unrelated to IQ and the correction of occipitofrontal circumference for dolichocephaly was rarely of clinical importance. Occipitofrontal circumference best correlated with the full scale IQ on the Wechsler Intelligence Scale for Children-Revised. At age 8 years the Wechsler IQ was significantly related to the OFC ratio in both very low birth weight and normal birth weight children. The AP-BP ratio was unrelated to IQ. [1]

COMMENT. The authors concluded that the National Center for Health Statistics data for occipitofrontal circumference measurements were more appropriate than the Nellhaus data in this study. Head growth achieved by age 8 years was progressively reduced in lower birth weight categories in all measurements except the anteroposterior diameter. Occipitofrontal circumference was closely related to IQ and other head measurements are not recommended in routine clinical practice. In a further report the authors found that maternal height and the birth weight ratio were more important than health after birth in predicting a height or weight below the 10th percentile at age 8 years in children with low birth weights. Occipitofrontal head circumference is related to infant development and later intelligence in childhood and is a useful indication of brain size.