We have developed an approach to elucidate the macrostructural changes of individual white matter tracts in neonatal brains, using deformation-based morphometry. Many studies have investigated how microstructure changes during development, however it is not clear how to disentangle changes in tissue microstructure from macrostructural volume changes. The latter is particularly challenging in the absence of longitudinal data from the same subject, which is the norm given the difficulty in scanning neonates. We propose an approach that is aimed towards this problem. Results are presented from analysis carried out on publicly available diffusion MRI data from the developing Human Connectome Project.