ZOE GONZALES / DAILY NEXUS
While we have long understood the profound changes that the human body undergoes during pregnancy, the transformation of the maternal brain has for the most part remained a mystery — until now. Researchers at UC Santa Barbara in the Jacobs Lab in collaboration with UC Irvine recently published a groundbreaking study in the journal Nature Neuroscience, the first of its kind, mapping a human brain throughout pregnancy and two years postpartum. Headed by associate professor Emily Jacobs and alumna Laura Pritschet of the psychological & brain sciences department at UCSB, the study marked a long-awaited breakthrough in understanding women’s health.
Over the course of preconception, pregnancy and postpartum, 26 magnetic resonance imaging (MRI) scans were taken of a first-time mother’s brain, with scans taken approximately every two weeks during pregnancy. The findings revealed widespread reductions in gray matter volume, which makes up the outer layer of the brain and cortical thickness, or the width, of this outer layer. On the other hand, white matter — the brain’s inner region responsible for facilitating connections between other parts of the brain — experienced an increase in volume. These changes occurred alongside a rise in sex hormone production associated with pregnancy.
The maternal brain’s transformation indicates a high level of neuroplasticity, or the brain’s ability to change and adapt. Hannah Grotzinger, study author and cognitive neuroscience doctoral candidate in the Jacobs Lab, shared the unexpected extent of these changes.
“I was surprised by how widespread the decreases in gray matter volume and cortical thickness were — about 80% of the 400 regions we looked at showed a significant decrease in size across pregnancy,” Grotzinger said. “There were not many brain regions that were left untouched by the transition to motherhood.”
The Jacobs Lab was the first to observe the maternal brain continuously throughout gestation, or the period of development of an embryo between conception and birth. According to Grotzinger, previous research has shown decreases in brain structures such as gray matter volume during pregnancy, but these studies only observed the brain at specific time points. In addition, the researchers found that changes such as decrease in gray matter volume are long-lasting and persist after two years postpartum, while the increase in white matter is more short-lived during pregnancy.
Given that 140 million women experience pregnancy annually and each of their brains undergoes a metamorphosis that is not fully understood, it is crucial to study how and why these changes occur. This research is taking the steps to hopefully improve our understanding of women’s health and conditions, such as postpartum depression and premenstrual dysphoric disorder.
“I hope that this work will serve as a baseline for typical brain development during matrescence, the transition to motherhood, so that we can begin to uncover a neural ‘fingerprint’ or biomarker in the brain for pregnancy-related conditions such as postpartum depression,” Grotzinger said. “This research is also important when we think about individual differences in aging trajectories — these changes seem to be long-lasting, so it’s important to know how pregnancy-related neural changes may impact the aging process.”
Grotzinger is continuing to research the maternal brain as well as observing how their non-pregnant partners might undergo brain changes during the transition to parenthood on the individual level.
“For my dissertation, I’m expanding data collection to a larger sample of prospective mothers and their non-pregnant partners, and I love working with our participants,” Grotzinger said. “Most of the women that have joined the study have expressed that they wanted to participate because they want answers — they want to know how and why their brains are changing during this transition to parenthood, and participating in this research can feel empowering.”
Grotzinger and the Jacobs Lab are collaborating with Ina Stelzer, a pregnancy immunologist and associate professor at UC San Diego, who aims to study the same participants’ changes in immune cells throughout pregnancy in order to provide more insight on how the brain is changing at the physiological level.
Despite this study being the first of its kind, the findings provide insight on the macroscopic scale, and it still isn’t fully understood how these large-scale brain changes are related to the physiological changes of pregnancy. However, this research and the participants involved are helping to provide an important stepping stone in the journey toward understanding women’s health.
“I love working in the field of maternal brain research because the work we’re doing is so novel and also crucial for advancing women’s health,” Grotzinger said. “We get to see the women in the study experience pregnancy and motherhood for the first time, and it feels really special to have this fantastic group of individuals contributing their brain scans in the pursuit of furthering our understanding of women’s brain health.”
A version of this article appeared on p.10 of the Oct. 17, 2024 edition of the Daily Nexus.
CORRECTION [10/18/2024, 2:49 p.m.]: A previous version of this article stated that Laura Pritschet is a graduate student of the psychological & brain sciences department at UC Santa Barbara. The article has been corrected to state that Pritschet is a UCSB alumna.
