Going through stress during pregnancy may have dire consequences for your unborn baby’s brain development with a new study linking stress with decreased cognitive development.

According to the new research by US researchers, not only do maternal stress, depression and anxiety negatively affect the cognitive outcomes of babies, but they also result in poor ability to manage emotional responses during parenting.

In the first study to shed light on a link between the developing brain in the uterus and long-term cognitive development consequences of high levels of stress, researchers from the Children’s National Hospital in Washington DC followed about 97 pregnant women and their babies. All pregnant participants were healthy, most had some level of education and were employed.

To quantify prenatal maternal stress, anxiety and depression, researchers used self-reported questionnaires. Foetal brain volumes and cortical folding were measured from 3D images derived from MRI scans. The children’s neurodevelopment was measured at 18 months.

While still in the womb, the researchers observed changes in the sulcal depth (folds in the outer part of the brain) and left hippocampal volume, which is associated with memory performance in brain. The changes suggested decreased cognitive development, which is seen after birth.

Researchers say once they grow into toddlers, these children may experience persistent social-emotional problems and have difficulty establishing positive relationships with others, including their mothers. The findings further suggest that persistent psychological distress after the baby is born may influence the parent-child interaction and infant self-regulation.

Writing in the American Medical Association (Jama) Network, lead researcher Yao Wu and colleagues said while the exact incidence of mental health disturbances in pregnant women is not known it is likely underestimated.

“In this study, all pregnant participants were healthy and had low-risk pregnancies, most were well educated and employed, and most were living in areas (such as Washington DC) with good access to healthcare. Despite these seemingly favourable conditions, 36% of participants exceeded the positivity threshold for stress, anxiety, and depression.”

They said the findings showed that prenatal maternal distress “may not be transient but persistent across the postnatal period with subsequent influences on both the parent-child interaction and infant self-regulation”.

“In addition, we found that prenatal maternal stress, even if not reaching the severity of a mental disorder, was associated with decreased infant cognitive performance. This finding is in keeping with results of previous studies showing cognitive impairments in children following early exposure to maternal stress.

“In particular, our findings suggest that this association may be partially mediated by foetal left hippocampal volume. Our findings suggest that though the prevalence of prenatal maternal distress in our cohort may not be as high as in the high-risk population, its association with infant outcomes cannot be ignored.”

Researcher Catherine Limperopoulos, who heads the Developing Brain Institute at the Children’s National Hospital, said by identifying the pregnant women with elevated levels of psychological distress, “clinicians could recognise those babies who are at risk for later neurodevelopmental impairment and might benefit from early, targeted interventions”.

Regardless of their socioeconomic status, about one out of four pregnant women suffers from stress-related symptoms, the most common pregnancy complication. The relationship between altered foetal brain development, prenatal maternal psychological distress and long-term neurodevelopmental outcomes remain unknown.

Researchers noted that studying in utero foetal brain development poses challenges due to foetal and maternal movements, imaging technology, signal-to-noise ratio issues and changes in brain growth.

The latest study builds on previous work from the brain institute led by Limperopoulos, which discovered that anxiety in pregnant women appears to affect the brain development of their babies. Her team also found that maternal mental health, even for women with high socioeconomic status, alters the structure and biochemistry of the developing foetal brain. The growing evidence underscores the importance of mental health support for pregnant women.

“We’re looking at shifting the healthcare paradigm and adopting these changes more broadly to better support moms. What’s clear is early interventions could help moms reduce their stress, which can positively impact their symptoms and thereby their baby long after birth,” said Limperopoulos.

TimesLIVE