Pregnancy physically changes the brain in expecting moms, landmark study finds

Scientists created the first-ever map of a human brain during the course of pregnancy

Becoming pregnant changes a woman’s brain, researchers say, in findings that could help doctors treat conditions developed by expecting moms.

A group of national scientists have created the first-ever map of a human brain during pregnancy, identifying a decrease in the brain’s gray matter and an increase in its white matter.

The body’s central nervous system is made up of gray and white matter. Gray matter is a type of tissue found in the brain and spinal cord, and plays a huge role in cognitive ability, memory, emotion, and movement. White matter, tissue found deeper inside the brain, helps the body to process information and connects regions that send and receive signals.

The finding could indicate that the adult brain is capable of undergoing an extended period of adaptive structural and functional changes that could help maternal behavior and bonding.

“The maternal brain undergoes a choreographed change across gestation, and we are finally able to see it unfold,” Emily Jacobs, whose lab at UC Santa Barbara led the research, said in a statement.

The findings were published Monday in the journal Nature Neuroscience.

A pregnant woman hold her belly. Scientists across the country announced they have created the first-ever map of a human brain during the course of their pregnancy, finding revealing changes. ((Katie Collins/PA Archive))

The study’s authors said gray matter shrank as a woman’s hormone production increased during her pregnancy – but said it is not necessarily ba. Instead, the change could demarcate a “fine-tuning” of the connections of the brain’s nerve cells, commonly known as neurons. This process is not unlike what happens to peoples’ brains during puberty, when the brain is reshaped. Although, the decrease in gray matter was apparent for longer periods following birth.

Conversely, an increase in white matter was fleeting, and peaked in the woman’s second trimester of pregnancy before returning to pre-pregnancy levels around the time of the birth. This was a change no one had ever captured before.

Laura Pritschet, a study co-author from UC Santa Barbara, told The Independent on Tuesday that their observations were sort of a “dance.”

“You can almost imagine this as a piece of marble and we’re etching it and sculpting it a lot more,” she explained. “Because, 140 million women are pregnant every year. If those were bad changes that were happening to the brain, this wouldn’t be as common [of] a phenomenon. It wouldn’t be the basis of our reproductive lives.”

Pritchet and the study’s authors note there there has been a gap of understanding in what is changing in the brain during the nine months of pregnancy: when hormones are rising and there are physiological studies. Previous studies had taken snapshots of the brain before and after pregnancy.

The findings could help scientists in the future deal with conditions that pregnant mothers face while carrying a baby or after they give birth. (Getty Images/iStock/Ratchat)

“It’s 2024 and this is the first time we have tracked someone’s brain throughout their pregnancy. Despite 85 percent of women experiencing one or more pregnancies in their lifetime,” Pritschet said.

Researchers took 26 images of co-author and UC Irvine associate professor Elizabeth Chrastil’s brain. Precision imaging was done before, during, and two years after her pregnancy.

Now, they hope to use these images to understand more of the brain’s adaptations, including the risks of postpartum depression and other neurological issues. About one in eight women who have recently given birth report symptoms of postpartum depression, according to the Centers for Disease Control and Prevention.

“We know there are a lot of neurological risks in pregnancy. So, can we understand, first, ‘What the brain is doing?’ Let’s map that,” Pritschet said. “Then, let’s go in and try to understand, ‘Can we take any of this information and better understand who’s at risk for these neurological conditions? And, can we find these neural signatures to try to provide some relief for women and try to get at who is at highest risk for adverse effects in postpartum?’”