Children’s brain development appears to be affected by their mother’s depressive symptoms in early pregnancy

A new study has found evidence of a link between prenatal maternal depressive symptoms and alterations in early brain development. The findings have been published in the journal Psychiatry Research: Neuroimaging.

“Child behavioral and emotional development as well as adult mental and physical health might be shaped by maternal depressive symptoms during pregnancy,” said researcher Henriette Acosta of the University of Turku. “The underlying biological mechanisms are not yet well understood and could involve alterations in fetal brain development.”

The study examined neuroimaging data from 28 children, who were scanned using magnetic resonance imaging when they were 4 years old. The children’s mothers had completed multiple assessments of anxiety and depressive symptoms during and after their pregnancy.

Acosta and her colleagues were particularly interested in a brain region known as the amygdala, which has been implicated in psychiatric disorders such as depression, post-traumatic stress disorder, schizophrenia and autism spectrum disorder.

After controlling for maternal anxiety, the researchers found that the children tended to have smaller right amygdalar volumes when their mothers experienced more depressive symptoms during pregnancy. Postnatal depressive symptoms, however, were not associated with amygdalar volumes.

“Higher maternal depressive symptoms during early and late pregnancy were associated with smaller subcortical brain volumes in 4-year-olds, which were more pronounced in boys than girls. The affected brain area, the amygdala, plays a prominent role in emotion processing and emotional memory and is implicated in several psychiatric disorders,” Acosta told PsyPost.

“The study results suggest that maternal depressive symptoms as early as in the prenatal period alter early brain development and might thus influence the offspring’s vulnerability to develop a mental disorder over the lifespan.”

The researchers controlled for a number of factors besides anxiety, including childhood maltreatment, maternal education, maternal age, prenatal medication, and maternal substance use. But the study — like all research — includes some limitations.

“A major caveat is the unknown role of underlying genetic effects that the child inherits from the mother and could impact child’s brain developmental trajectory as well as their vulnerability to stress and depression,” Acosta explained. “Moreover, the sample size of this study was rather small. Hence, the here reported findings should be addressed in future studies with larger sample sizes and genetically informed designs.”

Nevertheless, the study indicates that prenatal depression could have long-lasting effects on offspring health.

“The findings of this study support the notion that pregnancy constitutes a vulnerable period of an individual’s development and that the protection of the expectant mother from adversity should be a primary concern of society,” Acosta said.

The study, “Prenatal maternal depressive symptoms are associated with smaller amygdalar volumes of four-year-old children“, was published October 30, 2020.