Periodic Reporting for period 2 - PREGBRAIN (Pregnancy and the Human Brain: A Window of Neuroplasticity)
Reporting period: 2023-04-01 to 2024-09-30
Pregnancy represents one of the most extreme endocrine events of life. This transitional stage involves unequaled hormone surges that orchestrate widespread maternal adaptations. Animal studies have demonstrated reproduction-related neural and behavioral changes that are evident across the lifespan. However, remarkably little is known on the effects of pregnancy on the human brain. In this ERC project, we aim to map the changes in a woman’s brain by tracking core aspects of brain anatomy and function across pregnancy and the postpartum period. In addition, we investigate the factors that are driving this pregnancy-related neuroplasticity by means of an extensive profile of endocrine and lifestyle changes. Finally, we hope to increase our understanding of the implications of these brain changes for the mother-infant dyad and reveal neural substrates for potential adaptive and maladaptive processes. We investigate this novel topic by means of an innovative prospective cohort study tracking women from before conception across pregnancy and into the postpartum period, which combines cutting-edge neuroimaging approaches with various psychopedagogic and biomedical measures. The proposed project has the potential to generate groundbreaking insights into a woman’s remarkable neurobiological journey to motherhood.
During the course of this project, an extensive prospective cohort dataset will be collected in which women who want to become pregnant are investigated and followed throughout this trajectory. At the moment, we have completed the majority of the pre-pregnancy sessions and are continuously investigating women during their pregnancies and have just started with the postpartum follow-up sessions. The first 1-year postpartum follow-up sessions are planned this autumn. In addition, neuroimaging analyses of a dataset we have already collected have rendered various new insights. For instance, we have shown that pregnancy leads to selective and robust changes in brain architecture and neural network organization. These changes related to pregnancy hormones, especially third-trimester estradiol. Furthermore, the observed brain changes were associated with maternal processes such as nesting behavior, maternal-fetal bonding and the physiological responsiveness to infant cues. We also found that these changes predicted measures of mother-infant bonding and impairments in this bonding process. Analyses of the hypothalamus, a central structure of the mammalian maternal brain that is known to play a key role in the induction of maternal behavior in non-human mammals, revealed that becoming a mother is associated with anatomical changes in various substructures of this brain area. These changes related to hormone levels during pregnancy and to specific aspects of maternal behavior such as nesting behavior and maternal-fetal attachment. Together, these findings indicate that pregnancy is associated with hormone-driven changes in brain structure and function in humans and suggest that, similar to other mammals, these changes relate to the development of maternal behavior.
Since the start of this ERC project, we have already acquired various new insights regarding the impact of pregnancy and motherhood on the human brain. While we had previously discovered that pregnancy renders long-lasting changes in brain structure in humans, which was replicated in our current sample, we have now also shown that becoming a mother is associated with changes in brain function, more specifically in brain activity during rest. We have now also been able to link these with pregnancy hormones, especially estrogens in the third trimester, while no associations were found with other factors such as osmotic effects, stress and sleep. Finally, we found that these brain changes were related to various maternal processes that are of key relevance to the mother-infant dyad. Analyses of substructures of the hypothalamus also suggest that these brain changes contribute to the development of maternal behavior in humans and support the conservation of key aspects of maternal brain circuitry and their role in maternal behavior across species. These analyses have thus already rendered important insights into how pregnancy and motherhood change the human brain. Further analyses and datasets that we are working on will further elucidate how the brain is altered by becoming a mother and how these affect the mother and child, for instance by investigating changes in brain activity, cognition and behavior in relation to specific cognitive and social-emotional processes. In addition, we expect to learn more about the biological and environmental factors driving these changes and the implications for the mother.