A new study in the journal Nature Mental Health explores how a mother’s positive state of mind during pregnancy affects the structure and function of the developing fetal brain by measuring these parameters by 7.5 years of age.
Study: Maternal positive mental health during pregnancy impacts the hippocampus and functional brain networks in children. Image Credit: Dean Drobot / Shutterstock.com
How does the maternal emotional state affect fetal development?
During pregnancy, which is a time of significant physical, mental, and social change, anxiety, depression, and other stress-related mental health disorders are frequently reported. These mental health issues have been associated with a durable and adverse effect on fetal brain development.
For example, previous research has shown that these mental disorders can lead to changes in the growth rate of the fetal hippocampus and a lower density of gray matter in the prefrontal and medial temporal lobes in early childhood. These children may also exhibit altered structure and function of emotion-regulating cortico-limbic networks, which are important for stress management.
At certain stages, these changes appear to be more significant in girls than boys. Notably, it is not necessary that the mother be clinically anxious or depressed for these alterations to manifest.
As a key component of mental health, positive maternal emotions like happiness can affect multiple outcomes, including maternal-infant bonding, parenting approaches, and child development. Furthermore, maternal happiness during pregnancy also impacts the long-term health of both the mother and child; however, it remains unclear how positive maternal emotions affect prenatal development.
About the study
The current study used data from the Growing Up in Singapore Towards Health Outcomes (GUSTO) cohort. Both structural and functional magnetic resonance imaging (MRI) were performed on children to explore the association of maternal happiness during pregnancy with brain development.
The researchers developed their own tool to measure positive maternal mental health during pregnancy. This was based on a mental health questionnaire given to pregnant women at 26-28 weeks.
What did the study show?
At 7.5 years of age, children are experiencing a vital phase of development during which the brain shifts towards different patterns of activity and cognitive processes develop in new ways. As a result, this period was chosen as the focus of the study.
Brain areas involved in perceiving and regulating emotions include the hippocampus and amygdala, as well as various functional networks like the visual networks, default mode network (DMN), and functional network. These regions of the brain have also been directly correlated with how the mother cares for the child.
A composite measure from multiple mental health scales was used for assessing positive maternal emotions during pregnancy. Other potential contributing factors such as socioeconomic status, stress levels, family and friend relationships, and death of close relatives in the two years before and after pregnancy were also recorded to determine a socio-environmental adversity factor. Maternal parenting stress was also assessed when the child was six years of age.
Interestingly, girls born to mothers who reported feeling happy during pregnancy had larger hippocampus volumes, whereas both boys and girls born to happy mothers exhibited altered functional connectivity of multiple networks.
When categorized by task-negative and task-positive networks, reduced connectivity between task-negative networks was observed among girls born to mothers with increased positive emotions during pregnancy. Conversely, increased connectivity between task-positive networks was associated with greater maternal happiness during pregnancy.
Since these findings were absent when explored in relation to depression or anxiety in the mother during pregnancy, the observed changes in functional connectivity may occur specifically with greater maternal positive emotion in pregnancy. This may indicate that maternal happiness transmits to the developing child’s brain through neural changes.
What are the implications?
The study findings suggest that feeling happy during pregnancy not only reduces the risk of psychiatric illness in the mother but also potentially acts as a protective factor for fetal brain development.
Previous studies have shown that anxious and stressed mothers are more likely to have children with hippocampal changes, which may affect the developing brain and lead to impaired stress responses in the future. By encouraging mothers to have positive emotions during pregnancy, hippocampal development in the offspring may be promoted, with better structure and functional networks during the time when children typically begin to attend school.
Importantly, better hippocampal development is associated with greater childhood resilience, thus serving as an early marker for psychological vulnerability and greater potential for behavioral and emotional problems when encountering stressful circumstances. However, the period of fetal development at which maternal positive emotions occur may modify the impact.
Future studies are needed to establish and extend these findings, especially to understand the neural basis of prenatal-maternal interactions during psychoneurological development. These studies could support the development of preventive strategies to help mothers feel happy during pregnancy and ultimately promote the mental health of their children.
Journal reference:
- Qiu, A., Shen, C., Lopez-Vicente, M., et al. (2024). Maternal positive mental health during pregnancy impacts the hippocampus and functional brain networks in children. Nature Mental Health. doi:10.1038/s44220-024-00202-8.