Washington D.C. [USA], Jan 18 : Maternal stress, anxiety, and depression go a step higher if a fetus is found to have congenital heart disease (CHD). But this level of anxiety in pregnant mothers can lead to impaired development in key brain regions of the babies before they are born.
The study was published in the journal JAMA Pediatrics.
While additional research is needed, the Children's National Hospital study authors say their unprecedented findings underscore the need for universal screening for psychological distress as a routine part of prenatal care and taking other steps to support stressed-out pregnant women and safeguard their newborns' developing brains.
Catherine Limperopoulos, Ph.D., director of the Center for the Developing Brain at Children's National and the study's corresponding author, said, "We were alarmed by the high percentage of pregnant women with a diagnosis of a major fetal heart problem who tested positive for stress, anxiety, and depression."
"Equally concerning is how prevalent psychological distress is among pregnant women generally. We report for the first time that this challenging prenatal environment impairs regions of the fetal brain that play a major role in learning, memory, coordination, and social and behavioural development, making it all the more important for us to identify these women early during pregnancy to intervene," Limperopoulos added.
CHD or structural problems with the heart is the most common birth defect. Still, it remains unclear how exposure to maternal stress impacts brain development in fetuses with CHD.
The multidisciplinary study team enrolled 48 women whose unborn fetuses had been diagnosed with CHD and 92 healthy women with uncomplicated pregnancies. Using validated screening tools, they found that 65 percent of pregnant women expecting a baby with CHD tested positive for stress.
27 percent of women with uncomplicated pregnancies tested positive for stress, 44 percent of pregnant women expecting a baby with CHD tested positive for anxiety, 26 percent of women with uncomplicated pregnancies tested positive for anxiety, 29 percent of pregnant women expecting a baby with CHD tested positive for depression and, 9 percent women with uncomplicated pregnancies tested positive for depression.
All told, they performed 223 fetal magnetic resonance imaging sessions for these 140 fetuses between 21 and 40 weeks of gestation. They measured brain volume in cubic centimetres for the total brain as well as volumetric measurements for key regions such as the cerebrum, cerebellum, brainstem, and left and right hippocampus.
Maternal stress and anxiety in the second trimester were associated with smaller left hippocampi and smaller cerebellums only in pregnancies affected by fetal CHD. What's more, specific regions -- the hippocampus head and body and the left cerebellar lobe - were more susceptible to stunted growth.
The hippocampus is key to memory and learning, while the cerebellum controls motor coordination and plays a role in social and behavioural development.
The hippocampus is a brain structure that is known to be very sensitive to stress. The timing of the CHD diagnosis may have occurred at a particularly vulnerable time for the developing fetal cerebellum, which grows faster than any other brain structure in the second half of gestation, particularly in the third trimester.

Yao Wu, Ph.D., a research associate working with Limperopoulos at Children's National and the study's lead author said: "Our next goal is exploring effective prenatal cognitive-behavioral interventions to reduce psychological distress felt by pregnant women and improve neurodevelopment in babies with CHD."