Poverty, crime linked to differences in brains of newborns

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A new study has found that environmental factors impact the structure and function of young brains even before babies are born.

The investigation, published in JAMA Network Open, was conducted by researchers at Washington University School of Medicine in St. Louis, Missouri and sought to evaluate whether prenatal exposure to maternal social disadvantage and psychosocial stress was associated with global and relative infant brain volumes at birth. They found that MRI scans performed on healthy, sleeping newborns indicated that babies of mothers facing social disadvantages, such as poverty, tended to be born with smaller volumes across the entire brain than babies whose mothers had higher household incomes.

In addition, according to the study, the brain scans which were conducted only a few days to weeks after birth, also showed evidence of less folding of the brain among infants born to mothers living in poverty. Fewer and shallower folds typically signify brain immaturity.  

The research included 399 mother-infant dyads, but ultimately focused on 280 pairs of socially and demographically diverse mothers recruited in the first or early second trimester of pregnancy and their infants, who underwent brain magnetic resonance imaging during their first few weeks after birth. Mothers were recruited from local obstetric clinics in St Louis, Missouri from September 1, 2017, to February 28, 2020.

A second study of data from the same sample of 399 mothers and their babies, published in Biological Psychiatry, reported that pregnant mothers from neighborhoods with high crime rates gave birth to infants whose brains functioned differently during their first weeks of life than babies born to mothers living in safer neighborhoods. Functional MRI scans of babies whose mothers were exposed to crime displayed weaker connections between brain structures that process emotions and structures that help regulate and control those emotions, according to the study. Maternal stress is believed to be one of the reasons for the weaker connections in the babies’ brains.

“These studies demonstrate that a mother’s experiences during pregnancy can have a major impact on her infant’s brain development,” said Christopher D. Smyser, MD, one of the principal investigators, in a statement. “Like that old song about how the ‘knee bone is connected to the shin bone,’ there’s a saying about the brain, that ‘areas that fire together wire together.’ We’re analyzing how brain regions develop and form early functional networks because how those structures develop, and work together may have a major impact on long-term development and behavior.”