Research reveals intriguing clues about how pregnancy changes the brain.
Studies scanning women’s brains before and after pregnancy have found that certain brain networks, particularly those involved in social and emotional processing, shrink during pregnancy and undergo a fine-tuning process in preparation for child rearing. Such changes Pregnancy coincides with an increase in hormones, especially estrogen, and some last for at least two years after childbirth. Researchers have found.
A new studyPublished Monday in the journal Nature Neuroscience, it adds to the picture by documenting brain changes with MRIs throughout a woman’s pregnancy. This confirms earlier results and adds detail, in which white matter fibers showed the ability to effectively transmit signals between brain cells, a change that evaporated after birth.
“What’s really interesting about the current study is that it provides a detailed mapping,” said Elselin Hoeksema, a neuroscientist who heads the Pregnancy and Brain Laboratory at the University Medical Center Amsterdam. Before and after pregnancy.
Dr., who was not involved in the new study. Hoeksema said previously documented “long-term changes in brain structure and function show that more subtle, transient changes also occur.”
Dr. Ronald Dahl, director of the Human Development Institute at the University of California, Berkeley, who was not involved in the new study, said a growing body of research reflects the important role of hormones in changes like puberty and pregnancy, guiding neurological changes. Priorities and motivations.
“There’s a sense that it affects a lot of these systems,” he said.
Study participant Elizabeth Crostle is a neuroscientist at the University of California, Irvine. She became pregnant in 2019, at the age of 38, after a hysterectomy. This allowed her to accurately monitor her pregnancy from the beginning.
She had 26 brain MRIs — four scans before the pregnancy, which began three weeks ago; 15 during pregnancy; And seven in two years after the birth of her son in 2020.
“It was kind of fun to be a neurologist and find out what we didn’t know,” Dr. Crostle said, “so I thought, ‘Hey, let’s do this. I’m going to be pregnant. I think we should do this.’
She said she was not aware of any symptoms or effects associated with brain changes during pregnancy. However, his brain revealed profound differences.
By the ninth week of pregnancy, 80 percent of the 400 brain regions analyzed showed a decrease in gray matter volume and cortical thickness, which continued throughout pregnancy, with the regions shrinking by an average of 4 percent. The shift is particularly pronounced in the default mode network, a tool for perceiving the feelings and perspectives of others.
The study’s senior author, neuroscientist Emily Jacobs of the University of California, Santa Barbara, said that gestational brain shrinkage “isn’t a bad thing” and may have reflected pruning that “helps the brain become more specialized.” Similar processes occur during puberty and childhood and some neurological disorders arise from inadequate pruning, he noted.
As with Michelangelo’s statue of David, “the artist begins with these large blocks of marble, and the underlying beauty is revealed through the art of abstraction, careful polishing and fine adjustment of the material.” In this study, he said, “you can see the sculpting of the brain unfold week by week.”
Weight loss is often sustained for two years after giving birth, she said, as pregnancy hormones cause “permanent imprints on the brain.”
However, the white matter changes did not last. For reasons that are unclear, Dr. Crostle says that in the first two trimesters, fiber bundles become like roads with improved pavement, which “makes things run more smoothly, information can travel more seamlessly.” By delivery, the initial white matter level returns.
For comparison, the researchers evaluated brain imaging from eight non-pregnant individuals, including two men. Their brains showed no such changes.
But brain scans of several women’s pregnancies echoed Dr. Krastil’s pattern, Dr. Jacobs said.
Dr. Hoeksema said the method was so unique that his team showed that a computer algorithm could identify if women were pregnant “just based on changes in their brains.”
Her group’s research shows that “brain changes during pregnancy are associated with the way the mother’s brain and body function in the offspring,” she said, “correlating characteristics such as mother-fetal bonding, nesting behavior, and the heart rate of the female child.”
Dr. Dahl said pregnancy-related hormones may create neural “windows of learning” that “sensitize individuals to learn adaptive things, form bonds, and develop greater expertise in responding to a child.” Providing social and emotional support during pregnancy can be even more helpful because the brain is tuned to prioritize that information, she said.
However, the implications for parenting are undoubtedly complex and varied. For example, adoptive parents, fathers and others “may not experience pregnancy firsthand, but may display all the nurturing behaviors necessary to care for their children,” Dr. Jacobs said.
Studying brain changes during pregnancy may provide information about conditions such as postpartum depression and the neurological consequences of pre-eclampsia, the researchers say.
“We’re just beginning to scratch the surface of understanding,” Dr. Crostle said.
