Read the interview with Dr. Chrastil below.
WAM: You are a neuroscientist who decided to chart your own brain to see what we could learn about the changes that take place in a woman’s brain throughout her pregnancy. How did you come up with that idea in the first place, how did you do it, and what did you learn?
Dr. Chrastil: I do a lot of work on women’s brain health related to aging and menopause. Working with my collaborator Emily Jacobs, we had been working on how spatial navigation and memory changes across the menopause transition. During that time her student Laura Pritschet had done a project with repeated scans across the menstrual cycle. When I was planning a pregnancy I came to them with the idea to do something similar with pregnancy – let’s scan my own brain before, during, and after pregnancy to see how it changes.
We found that gray matter volume – the main parts of the nerve cells – decreased around 4% on average, with a pretty steady decrease in volume the whole time and only a little rebound postpartum. The white matter – the axons of the nerve cells which allow for communication far across the brain – had an increase in its structural integrity during pregnancy, which then returned to baseline. Overall, the results suggest that there are large changes during pregnancy, some of which return. Others are long-lasting. We are still trying to determine what they mean for people in the long run – does this affect parental behavior?
WAM: What are some of the most common cognitive and emotional symptoms pregnant women and young mothers report, and how might your findings help explain them?
Dr. Chrastil: About 15% of women will experience postpartum depression, which can have devastating consequences. Many women experience memory problems and “brain fog” during pregnancy and postpartum, but we still don’t have a complete grasp on what kinds of cognitive and emotional changes occur. In particular, there are many other things happening at the same time, especially a lack of sleep, stress, and anxiety, so it is difficult to know what is attributable to the pregnancy specifically versus other factors that are happening. But our results do suggest that there are rapid changes in brain structure, which could potentially drive changes in memory or attention that many women experience. This research also opens the door to understanding why some people are really affected and others are not affected as much – we hope in the future to see the variety in how women’s brains change to see if that is related to some of these mental symptoms.
WAM: Your research revealed reduced gray matter volume during pregnancy. Could you explain what this means for cognitive function and why it’s actually a positive development?
Dr. Chrastil: We don’t totally know what it means just yet, but it is likely adaptive. A reduction in volume is not necessarily a bad thing: we know that there is significant pruning at other transition stages in life, which could be related to more efficient processing. Another study that compared brain volume before and after pregnancy found that the reduction in gray matter volume was related to measures of maternal attachment, which suggests that these changes during pregnancy are important for the transition to motherhood.
On the other hand, we saw increases in white matter integrity, which could also be important for communication across brain regions. This increase peaked around the 2nd/3rd trimester and returned to baseline, and we don’t fully know how this change is adaptive.
WAM: Your team’s research suggests matrescence is a distinct developmental stage similar to adolescence. How might understanding this framework change our approach to maternal care?
Dr. Chrastil: There is often an assumption that once the brain is finished developing from childhood (which actually finishes around age 25), that it is done and there are no other major reorganization events. Our research shows that pregnancy is another major time of plasticity, when there are large-scale changes in brain structure. In adolescence there is extensive reorganization and pruning – some of the brain connections go away. This might slow down things like learning but can be really helpful for consistent behaviors and using your experience. During pregnancy there is also preparation for a major life change, taking care of an infant and trying to understand its needs, and we think that could be important enough that the brain needs to change.
WAM: We still know so little about women’s brains during pregnancy. What are the most critical gaps in our understanding that future research should address?
Dr. Chrastil: There are so many gaps! Right now our work is only on one person, but we are expanding it to more women so that we can get a better understanding of how people differ in their pregnancy experiences. With an expanded team of collaborators, we are planning on recruiting a more diverse population so that we can understand more about how women differ. The big questions still remain: do these brain changes affect behavior, cognition, and parental care? Can we determine who is at risk for things like preeclampsia and postpartum depression? Can we figure out the best time to intervene with prevention and treatment for depression? Why do some women experience improvement in migraines during pregnancy, and others get worse? I’m so excited to see the interest in pregnancy growing, with many research groups tackling different issues.
WAM: Did watching your own brain change throughout the pregnancy impact how you felt about your pregnancy journey or give you an insight into neurology you didn’t expect?
Dr. Chrastil: Fortunately, we didn’t look at any of the data until we had finished the first 6 months postpartum. I think it might have made me a little crazy to see things change while it was happening. But looking back on things, I know that I felt different little by little, and we do see these accumulating changes over the course of pregnancy. There were some things that I would not have expected, like the increase in white matter integrity. I personally didn’t have too many brain fog symptoms, yet there are clearly a lot of changes that are occurring even so, which you might not be able to feel directly, but are still happening.
WAM: Do you have anything else you’d like for us to know?
Dr. Chrastil: Our study opens up more questions than it answers. The most important thing about the study is probably that we did it at all – we asked a question that hadn’t been addressed over decades of research. It is pretty shocking that in 2025 we still know so little about how the brain changes during some of these major transitions in women’s health – pregnancy, menopause – and we hope that this study spurs on the field to find out more.