For adults and children, violence and poverty are often seen as public health issues. Now, new scientific evidence suggests crime and poverty can affect the structure and function of children’s brains even before birth.

Using MRI scans, researchers at Washington University in St. Louis have found that socially disadvantaged mothers tended to have babies with smaller brains than those born to wealthier mothers. The brain scans, which were taken a few days after birth from 250 infants, revealed smaller brain volumes as well as less folding. Fewer and shallower brain folds are indicators of brain immaturity and can affect future development.

Poverty isn’t the only factor affecting newborns’ development. A second study of data from 399 mothers and babies showed that mothers from high-crime neighborhoods gave birth to children whose brains functioned differently than the brains of babies born in safer areas. The babies from higher-crime areas had weaker connections in the brain areas that process and control emotions. Maternal stress is believed to contribute to the weaker connections in the babies’ brains.

Each of the factors appears to affect infants’ brains in different ways, with poverty affecting brain-wide development and exposure to crime influencing development of specific brain areas.

The researchers said the findings are crucial to informed debates about public health and public policy. In practical terms, they noted, helping expectant mothers out of poverty and protecting them from crime is a way to help children even before they’re born.