Social disadvantages impacts fetal brain development

Published in the journal 'Proceedings of the National Academy of Sciences' (PNAS), a new study found links between social disadvantages and fetal brain development.

Researchers examined 289 healthy newborns from socially diverse families in the United States using diffusion MRI scans shortly after birth. The analysis revealed that prenatal exposure to measures of social disadvantage was associated with altered microstructure of white matter in frontolimbic pathways of the brain that are important for socioemotional development.

Early life adversity (social disadvantage and psychosocial stressors) is associated with altered microstructure in fronto-limbic pathways important for socioemotional development.

Understanding when these associations begin to emerge may inform the timing and design of preventative interventions. In this longitudinal study, 399 mothers were oversampled for low income and completed social background measures during pregnancy.

Measures were analyzed with structural equation analysis resulting in two latent factors: social disadvantage (education, insurance status, income-to-needs ratio [INR], neighborhood deprivation, and nutrition) and psychosocial stress (depression, stress, life events, and racial discrimination). At birth, 289 healthy term-born neonates underwent a diffusion MRI (dMRI) scan.

Mean diffusivity (MD) and fractional anisotropy (FA) were measured for the dorsal and inferior cingulum bundle (CB), uncinate, and fornix using probabilistic tractography in FSL. Social disadvantage and psychosocial stress were fitted to dMRI parameters using regression models adjusted for infant postmenstrual age at scan and sex. Social disadvantage, but not psychosocial stress, was independently associated with lower MD in the bilateral inferior CB and left uncinate, right fornix, and lower MD and higher FA in the right dorsal CB.

Results persisted after accounting for maternal medical morbidities and prenatal drug exposure.

In moderation analysis, psychosocial stress was associated with lower MD in the left inferior CB among the lower-to-higher socioeconomic status (SES) (INR >= 200 per cent) group, but not the extremely low SES (INR < 200 per cent) group. Increasing access to social welfare programs that reduce the burden of social disadvantage and related psychosocial stressors may be an important target to protect fetal brain development in fronto-limbic pathways.