Background & aims: Glutamine supplementation in the neonatal period has been associated with increased brain structure volumes at school-age in very preterm children. The aim of this study was to clarify the emergence and specificity of differences in brain structure volumes, using growth trajectories of head circumference, weight, and length. Methods: Sixty-five very preterm (<32 weeks gestation) children, who originally took part in a randomized controlled trial on glutamine supplementation, participated. Head circumference, weight, and length, were measured at the neonatal intensive care unit, and at routine follow-up assessments at the outpatient clinic and well baby clinics. Magnetic Resonance Imaging was used to determine brain structure volumes at school-age. Growth trajectories were investigated using multilevel modeling analyses. Results: Head circumference in the first year of life was positively associated with white matter volume and grey matter volume (range r=0.55-0.81, all p<0.002) at school-age. Furthermore, neonatal glutamine supplementation was associated with increased head circumference growth (p=0.008) in the first year of life, but not with increased growth in weight (p=0.44) and length (p=0.73). Conclusions: This study indicates a specific increase in head circumference growth in very preterm children that received neonatal glutamine supplementation, and suggests that group differences in brain structure volumes at school-age may have emerged during the first year of life. © 2013 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism.