Babies of mothers who experience significant psychological distress during pregnancy showed evidence of altered brain development in utero and reduced cognitive outcomes at 18 months, based on data from a pair of studies including approximately 300 women.
In a longitudinal study published in JAMA Network Open, Yao Wu, PhD, of Children’s National Hospital, Washington, and colleagues recruited 97 healthy mother-infant dyads between January 2016 and October 2020 at a single center. Of these, 87 underwent two fetal brain imaging studies each, and 10 completed the first MRI visit, for a total of 184 fetal MRIs.
Neurodevelopment and social-emotional development for infants at 18 months of age was measured using the Bayley Scales of Infant and Toddler Development and Infant-Toddler Social and Emotional Assessment. The mean age of the mothers was 35 years; maternal distress was assessed between 24 and 40 weeks’ gestation using validated self-report questionnaires. Parenting stress was assessed at the 18-month infant testing using the Parenting Stress Index-Short Form.
Overall, prenatal maternal stress was negatively associated with infant cognitive performance (P = .01) at 18 months, mediated by fetal left hippocampal volume.
In addition, increased fetal cortical local gyrification index and sulcal depth measured during reported times of prenatal maternal distress were associated with significantly poorer social-emotional scores and competence scores at age 18 months. The beta coefficients for local gyrification index and sulcal depth were –54.62 and –14.22, respectively, for social-emotional and competence scores, –24.01 and –7.53, respectively; P values were P < .001, P < .002, P = .003, P < .001, respectively.
“Increased cortical gyrification has been suggested in children with dyslexia and autism, and sulcal depth has been associated with the severity of impaired performance on working memory and executive function in adults with schizophrenia,” the researchers wrote in their discussion of the findings.
The current study “extends our previous findings and suggests a critical role for disturbances in emerging fetal cerebral cortical folding development in mediating the association between prenatal maternal distress and neurodevelopmental problems that later manifest in infancy,” they explained.
The researchers also found that prenatal maternal anxiety, stress, and depression were positively associated with all measures of parenting stress at the 18-month testing visit.
The study findings were limited by several factors including the use of self-reports for both maternal distress and infant social-emotional assessment, despite the use of validated questionnaires, and the fact that assessment of maternal distress at specific times may not reflect the entire pregnancy, the researchers noted. Other potential limitations included the inability to use some MRI data because of fetal movement and the homogenous population of relatively highly educated women with access to health care that may not reflect other areas, they said.
“Identifying early brain developmental biomarkers may help improve the identification of infants at risk for later neurodevelopmental impairment who might benefit from early targeted interventions,” the researchers concluded.
Technology enhances health and disease models
The effect of the prenatal period on future well-being is recognized, but the current study makes “substantial contributions to prenatal programming science, with implications for ways to transform the prenatal care ecosystem for two-generation impact,” Catherine Monk, PhD, and Cristina R. Fernández, MD, both of Columbia University, New York, wrote in an accompanying editorial.
John Abbott/Columbia University
Dr. Catherine Monk
The developmental origins of health and disease (DOHaD) conceptual model introduced by Dr. David Barker in 1995 were later applied to show that maternal stress, depression, and anxiety affected child prenatal and future development, they said. However, the current study uses cutting-edge neuroscience to directly assess developing fetal brains. The finding of reduced cognitive functioning at 18 months associated with maternal stress is consistent with other findings, they noted.
“Finding an association between maternal prenatal stress and infant cognitive outcomes in the setting of what may be modest stress relative to that of a low-resourced or historically marginalized sample underscores the importance of this research; presumably, with higher stress, and greater social determinants of health burden, the effect sizes would be even greater and of greater concern,” they said.
However, studies such as the current one “have the potential to transform the prenatal and postpartum care ecosystems,” by encouraging a whole-person approach to the care of pregnant women, including attention to mental well-being and quality of life, they emphasized.
COVID-19 stress considerations
In a separate study published in Communications Medicine, Yuan-Chiao Lu, MD, also of Children’s National Hospital in Washington, and colleagues found a similar effect of maternal stress on fetal brain development.
The researchers imaged the brains of fetuses before and during the COVID-19 pandemic and interviewed mothers about any distress they experienced during pregnancy.
The study population included 65 women with known COVID-19 exposures who underwent 92 fetal MRIs and 137 prepandemic controls who underwent 182 fetal MRIs. Maternal distress was measured via the Spielberger State Anxiety Inventory, Spielberger Trait Anxiety Inventory, Perceived Stress Scale, and Edinburgh Postnatal Depression Scale.
Overall, scores on measures of stress and depression were significantly higher for women in the pandemic group compared with controls. Of the 173 women for whom maternal distress measures were available, 28% of the prepandemic group and 52% of the pandemic group met criteria for elevated maternal psychological distress, defined as above the threshold for distress on any one of the four measures.
After the researchers controlled for maternal distress, MRI data showed decreases in fetal white matter and in hippocampal and cerebellar volumes in fetuses in the pandemic group compared with controls.
Other signs of impaired brain development were similar to those seen in the JAMA Network Open study, including decreased cortical surface area and local gyrification index, as well as reduced sulcal depth in multiple brain lobes, indicating delayed cerebral cortical gyrification.
The second study was limited by a lack of data on other lifestyle changes during the pandemic that might influence maternal health and fetal development, the researchers noted. Other limitations were the possible lack of generalizability to a range of racial and ethnic populations and geographic areas outside of Washington, and the inability to control for unknown COVID-19 exposures or subclinical infections in controls, they said.
However, the results support findings from previous studies, and provide a unique opportunity to study the effect of prenatal stress on early development, as well as a chance to implement “novel and timely interventions,” the researchers wrote.
“Monitoring the COVID generation of infants for long-term cognitive and health outcomes after birth is warranted and currently underway,” and continued research may inform preventive strategies for pregnant women experiencing multiple stressors beyond the pandemic, they concluded.