Summary: A new study provides the first detailed map of brain changes during pregnancy and shows remarkable neuroplasticity in adulthood. Researchers found that the brain’s gray matter volume decreases and white matter temporarily increases during pregnancy.
These changes are thought to fine-tune brain circuitry for the demands of motherhood.The study could improve our understanding of brain ageing and help detect early risk of postnatal depression.
Key Facts:
Pregnancy reduces grey matter and temporarily increases white matter, changes in the brain that may help adapt to the demands of parenting. This discovery may lead to improved detection of risk for postpartum depression.
Source: University of California, Santa Barbara
We all know that pregnancy is a transformative time in life, when the body undergoes rapid physiological adaptations in preparation for motherhood. How the rapid hormonal changes brought about by pregnancy affect the brain remains a mystery.
Researchers in the lab of Professor Emily Jacobs at the University of California, Santa Barbara, have created the first map of the human brain during pregnancy, shedding light on this little-studied area.
“We specifically wanted to look at the trajectory of brain change across pregnancy,” said Laura Pritchett, lead author of the paper just published in Nature Neuroscience.
Previous studies have taken snapshots of the brain before and after pregnancy, but they’ve never been able to observe the brain changing in this way during pregnancy, she said.
The researchers followed one first-time mother, scanning her brain from before her pregnancy until every few weeks for two years after giving birth.
The data, collected in collaboration with Elisabeth Krustil’s team at the University of California, Irvine, reveal changes in the brain’s grey and white matter throughout pregnancy and suggest that the brain is capable of remarkable neuroplasticity into adulthood.
The sophisticated imaging technique allowed them to capture the dynamic reorganization of the subjects’ brains in exquisite detail. This complements earlier studies comparing women’s brains before and after pregnancy. “Our goal was to fill that gap and understand the neurobiological changes that occur during pregnancy itself,” the authors write.
Decreased gray matter, increased white matter
The most striking change the scientists found when they imaged the subjects’ brains over time was a decrease in the volume of cortical gray matter, the wrinkled outer part of the brain. Gray matter volume decreased as hormone production increased during pregnancy.
But the scientists stressed that a decrease in gray matter volume isn’t necessarily a bad thing. The change could indicate a “fine-tuning” of brain circuitry, similar to what happens in all young people as they go through puberty and their brains become more specialized. Pregnancy is more likely to reflect a period of further cortical refinement.
“Laura Pritchett and her team have done an outstanding job, conducting a series of rigorous analyses that have produced new insights into the human brain and its remarkable capacity for plasticity in adulthood,” Jacobs said.
Less obviously, but equally important, the researchers found a significant increase in white matter, which lies deeper in the brain and is generally responsible for facilitating communication between brain regions.
The loss of gray matter continued long after birth, whereas the increase in white matter was temporary, peaking during mid-pregnancy and returning to pre-pregnancy levels around the time of birth.
This kind of effect has never before been captured in before-and-after scans, the researchers say, allowing them to better estimate just how dynamic the brain can be over a relatively short period of time.
“The mother’s brain undergoes deliberate changes during pregnancy and we are finally able to see how they unfold,” Jacobs said.
These changes suggest that the adult brain can undergo long-term neuroplasticity, brain changes that support behavioral adaptations associated with parenting.
“85% of women will experience at least one pregnancy in their lifetime and approximately 140 million women become pregnant each year,” said Pritchett, who hopes to “dispel myths” about the vulnerability of pregnant women.
She argued that the neuroscience of pregnancy should not be seen as a niche research topic, as discoveries made through this work would “improve our overall understanding of the human brain, including the ageing process”.
The open-access dataset, available online, provides a starting point for future research to understand whether the magnitude and pace of these brain changes might offer clues about risk of postpartum depression, a neurological disorder that affects about one in five women.
“While there are FDA-approved treatments for postpartum depression, early detection remains difficult, and the more we learn about the maternal brain, the better our chances of alleviating symptoms,” Pritchett said.
And that’s exactly what the authors set out to do. With support from the Ann S. Bowers Women’s Brain Health Initiative, which Jacobs directs, their team is building on these early findings through the Maternal Brain Project.
Many more women and their partners are being enrolled through international collaborations with researchers at the University of California, Santa Barbara, the University of California, Irvine, and Spain.
“Experts in neuroscience, reproductive immunology, proteomics and AI are joining forces to learn more than ever before about the maternal brain,” Jacobs said. “Together, we have the opportunity to address some of the most pressing and least understood problems in women’s health.”
About this research news on neuroplasticity and pregnancy
Author: Sonia Fernandez
Source: University of California, Santa Barbara
Contact: Sonia Fernandez – University of California, Santa Barbara
Image: This image is provided by Neuroscience News
Original research: Open Access.
“Neuroanatomical changes during human pregnancy,” by Emily Jacobs et al., Nature Neuroscience
Abstract
Neuroanatomical changes observed during human pregnancy
Pregnancy is a period of major hormonal and physiological change experienced by millions of women each year, yet the neural changes that occur in the maternal brain during pregnancy have not been well studied in humans.
Using precision imaging, we mapped neuroanatomical changes in individuals from pre-pregnancy to 2 years after birth. We found a marked decrease in grey matter volume and cortical thickness throughout the brain, contrasting with increases in white matter microstructural integrity, ventricular volume, and cerebrospinal fluid. Few regions were unaffected by the transition to motherhood.
This dataset serves as a comprehensive map of the human brain across the entire gestational age and provides an open-access resource for the brain imaging community to further explore and understand the maternal brain.