Pregnant Mother's Stress Affects Baby's Brain

According to research published online Jan. 13, 2020, in JAMA Pediatrics, maternal stress, anxiety and depression cause women's fetuses to end up with impaired development in key brain regions before they are born.

The Children's National Hospital study authors note that their unprecedented findings underscore the need for universal screening for psychological distress as a routine part of prenatal care. They also say taking other steps would be beneficial to support stressed-out pregnant women and to safeguard their newborns' developing brains.

In another study published in the journal Biological Psychiatry, babies whose mothers experienced more stress before birth could be born with an impaired part of the brain that has previously been linked to psychiatric disorders.

The afflicted area of the brain is called the uncinate fasciculus, which is a white matter tract that connects parts of the limbic system.

Researchers from King's College London examined 251 premature babies and their mothers to investigate for the first time the relationship between maternal stress and a child's brain development.

Women who were more stressed before or during pregnancy gave birth to babies whose white matter developed differently.

The researchers did not look at how these brain changes affect behavior.

The mothers of the babies were asked to complete a questionnaire that asked them about their experiences of stressful events, citing events that ranged from everyday stress, such as moving house or taking an exam, to more severe stress such as bereavement, separation or divorce.

When a mother is stressed, anxious or depressed while pregnant, her child is at increased risk for having a range of problems, including emotional problems, ADHD, conduct disorder and impaired cognitive development. Both altered brain structure and function are linked with prenatal stress, and also the mother's experience of early childhood trauma.

These findings show more work is needed to support the mental wellbeing of expectant mothers.

According to lead author Alexandra Lautarescu, a doctoral researcher from King's College London, while pregnant women are often asked by their GPs to state whether or not they've experienced depression or anxiety, they are rarely asked about general stress levels.

Genetic transmission and the quality of postnatal care are also likely to contribute to some of these findings of association.

Several large cohort studies have found associations independent of possible confounding factors, including birth weight, gestational age, maternal education, smoking, alcohol consumption, and most importantly, postnatal anxiety and depression.

One of the possible reasons behind the studies is that stress hormones, such as cortisol, reach the baby in the womb through the placenta.

More than one in ten babies are born prematurely worldwide, having been born before the 37th week of pregnancy.

Elysia Poggi Davis from the University of Denver emphasized, "I think we're becoming aware that we have to start thinking of these things during pregnancy, not waiting until after the baby is born."

The more the exposure to Mom's cortisol in the womb, the larger was the infants' cortisol spike in response to a blood draw on the first day of life.

In the findings, maternal cortisol can pass through the placenta and that infants born to mothers who experienced a mood disorder during pregnancy show increased cortisol and norepinephrine, as well as decreased dopamine and serotonin.