Babies born preterm are known to be at risk of alterations in brain structure and connectivity. Research by Scottish investigators shows that the structure of the white matter in their brains may improve with increased exposure to breastmilk.
Published in NeuroImage, the results are from a cohort of 47 infants born at ≤ 33 weeks treated at the Royal Infirmary in Edinburgh. They underwent brain magnetic resonance imaging at term-equivalent age as part of a longitudinal investigation of the effects of preterm birth on brain structure and outcome.
The researchers assessed the MRI results and information about the infants’ neonatal breastmilk exposure to test the hypothesis that breastfeeding is associated with improved markers of brain development and connectivity in preterm infants at term-equivalent age. Network-Based Statistics, Tract-based Spatial Statistics (TBSS), and volumetric analysis were used to investigate the effect of breastmilk exposure on white matter diffusion parameters, tissue volumes, and the structural connectome.
Of the infants, 27 were exclusively breastfed for ≥ 75% of their time at the Royal Infirmary and 20 were breastfed for < 75% of that time. The higher exposure to breastmilk was associated with higher connectivity in the fractional anisotropy (FA)-weight connectome compared with the connectivity in the brains of the infants who had fewer breastmilk days (P= 0.04).
Within the TBSS white matter skeleton, the infants who received more breastmilk had higher FA within the corpus callosum, cingulum cingulate gyri, centrum semiovale, corticospinal tracts, arcuate fasciculi and posterior limbs of the internal capsule. The difference between the two groups was unchanged after adjustment for postmenstrual age at birth or at image acquisition, bronchopulmonary dysplasia, and chorioamnionitis (P< 0.05).
The investigators noted that the positive effects of breastmilk on the brain appeared to be dose-dependent, because connectivity in neural systems was further increased in infants who received breastmilk on ≥ 90% of days in the Royal Infirmary (P= 0.0086). The authors said the effects they observed are unlikely to be attributable to parenteral nutrition because exposure to it did not differ significantly between the two groups.
The main strength of the study, the researchers said, was the comprehensive assessment of brain development using three measures of the encephalopathy of prematurity: connectivity, tract microstructure, and local and global brain volumes. It was limited in that the authors could not investigate the effect of common genetic variation in metabolism of fatty acids and the cohort was not large enough to allow study of the effect of donor expressed breastmilk or human milk fortifier on brain development.