In a recent study published in the journal „Nature Mental Health,“ researchers examined the link between the mental health of mothers and the brain development of children. Their findings contribute to the medical understanding of the importance of the intrauterine environment and suggest that emotional well-being during pregnancy may be an important protective factor for children’s brain development, in addition to positive outcomes for the mother.
Study: Maternal happiness during pregnancy linked to child’s brain development. Image Source: Prostock-studio / Shutterstock
Research suggests that depression, anxiety, and stress during pregnancy may have lasting negative effects on the brain development of the child. Maternal anxieties and depressions have been found to affect the density of gray matter in the medial temporal and prefrontal cortex, as well as the growth of the hippocampus.
The mother’s health factors can also alter the cortico-limbic system, which helps regulate stress responses and emotional states. These far-reaching effects have been observed to be more pronounced in female children between birth and early childhood. These results highlight the need to address prenatal mental health in order to promote brain development in children.
However, emotional well-being does not only mean the absence of mental illness, but also includes experiencing positive emotions and mental affects. While the impact of positive maternal emotions on parenting behavior, mother-child bonding, long-term mental health, and child development has been studied, their effects on brain development have not been investigated.
About the Study
The study followed a longitudinal prospective birth cohort design to examine the link between maternal well-being and brain development in 7.5-year-old children using magnetic resonance imaging (MRI). This age was chosen because it is an important phase of neurological development where significant cognitive processes and brain changes occur.
The study participants included pregnant Asian (Malay, Indian, or Chinese) women in the first trimester recruited during their prenatal care at an ultrasound clinic in Singapore. For the MRI, children with a gestational age of more than 30 weeks and a birth weight of more than 2 kg were included to avoid the confounding effects of birth complications.
The authors hypothesized that positive emotions during pregnancy would be associated with significant differences in brain structures such as the amygdala and hippocampus, as well as in functional networks such as the default mode and visual networks. The mental health of the mothers was assessed using the Beck Depression Inventory, the Edinburgh Postnatal Depression Scale, and the State-Trait Anxiety Inventory.
In addition, the survey included questions about socioeconomic status, relationships with friends and family, life stress, and other factors related to prenatal health and well-being. This information was used to create an overall socioecological adversity factor and ratings for four risk areas – personal, interpersonal, socioeconomic, and life stress.
The sample of participants who underwent structural MRI included 381 children, of which 369 also underwent functional MRI. After controlling for the overall socioecological adversity factor and child age during MRI, the researchers found that more positive maternal emotions during the prenatal phase were associated with a larger bilateral hippocampus volume in female children, but not in male children. However, no connection was found between positive emotions of the mother and cortical thickness or the volume of the thalamus, amygdala, lateral ventricles, or basal ganglia.
In terms of functional networks, more maternal positive emotions were associated with higher functional connectivity between the right frontoparietal and visual association networks, salience and thalamo-hippocampal networks, and posterior default mode and attention networks. Remarkably, these results were significant after accounting for the child’s gender and age, as well as postnatal parenting stress and other risk factors. However, these results were not associated with anxiety or depressive symptoms during pregnancy.
These findings suggest that there may be a neural basis through which positive emotions during pregnancy are transmitted from the mother to their offspring during early brain development. Only the change in bilateral hippocampi between male and female children differed from significantly associated results. This research suggests that ensuring the mental health of mothers could lead to sustainable benefits for offspring in terms of neural development.
While the study has several strengths and provides new insights, the authors acknowledged some limitations. While brain development was assessed through neuroimaging, data on maternal mood and well-being were collected through subjective reports and may be subject to biases related to memory and social desirability. Self-reports of positive emotions may not be a sufficient indicator of mental well-being, a complex and multifaceted issue. The study participants were all Asians, leading to a lack of generalizability to other populations.
Future studies can build on these findings by including individuals of other races and considering positive emotions in other phases (e.g., postpartum period). This work adds to a growing body of literature demonstrating the intergenerational nature of mental health outcomes and underscores the importance of ensuring that mothers and children are not only healthy, but also happy.
- Maternal happiness during pregnancy linked to child’s brain development. Qui, A., Shen, C., López-Vicente, M., Szekely, E., Chong, Y., White, T., Wazana, A. Nature Mental Health (2024). DOI: 10.1038/s44220-024-00202-8, https://www.nature.com/articles/s44220-024-00202-8