Study: Babies whose moms had high pandemic stress had altered brain growth

The infants of mothers with high anxiety and stress levels amid the COVID-19 pandemic showed differences in brain development, suggests a study posted today in JAMA Network Open.

A team led by Children’s National Hospital researchers in Washington, DC, used magnetic resonance imaging (MRI) to compare regional brain volumes in 159 infants born during the pandemic (June 2020 to June 2022; 56 newborns) to those of healthy infants recruited before (March 2014 to December 2019; 103). The 159 mothers’ distress was evaluated using the Spielberger State-Trait Anxiety Inventory and the Perceived Stress Scale.

The median gestational age was 39.6 weeks, and the median maternal age was 34.5 years. Slightly over half (52.2%) of infants were girls. A total of 55.3% of mothers were White; 27.7% were Asian, Hispanic, or multiracial; and 17.0% were Black.

Reduced white matter, amygdala, hippocampus

Among women in the prepandemic cohort, 21.1% scored above the threshold for anxiety (state, 12.8%; trait, 13.8%), and 24.7% scored high for stress. In total, 28.4% in the prepandemic group scored high on the pooled metric of psychological distress. 

In the pandemic cohort, 61.8% scored above the threshold for anxiety (state, 56.4%; trait, 45.5%), and 69.1% scored above the threshold for stress. Overall, 72.7% in that group scored above the threshold for psychological distress. The proportion of women who scored above the threshold for each metric was significantly greater in the pandemic cohort than in the prepandemic cohort.

The extent to which these neonatal brain findings serve as early indices of risk for later social and emotional development are unknown.

Newborns of mothers with elevated distress showed median reductions in brain volumes of white matter (−0.36 cubic centimeters [cm³]), right hippocampus (−0.35 cm³), and left amygdala (−0.49 cm³) compared with infants of women with low distress. 

After adjustment for pandemic effects, elevated trait anxiety stayed significantly tied to decreased left amygdalar volumes (−0.71 cm³), and high maternal psychological distress was inversely associated with white matter (−4.94 cm³) and left amygdalar (−0.03 cm³) volumes. In particular, elevated maternal state and trait anxiety were tied to lower left-amygdalar volume (−0.03 and −0.04 cm³, respectively). 

Elevated maternal stress was associated with decreased left-amygdalar volumes (−0.03 cm³). Left amygdalar volumes remained significantly lower for mothers with elevated trait anxiety (−0.71 cm³) after adjustment.

“The extent to which these neonatal brain findings serve as early indices of risk for later social and emotional development are unknown,” the researchers wrote. “Further studies into the long-term impact on offspring development are needed and currently under way.”