For the first time, researchers have captured significant changes in the human brain during pregnancy using precision MRI scans. This groundbreaking study provides insights into the brain's reorganization in expectant mothers and sheds light on short-term and long-lasting neurological changes. The research is crucial to understanding the maternal brain, laying the foundation for further studies into pregnancy-related conditions like postnatal depression, pre-eclampsia, and their links to dementia.

The research team, led by scientists at the University of California, performed detailed brain scans on a healthy 38-year-old woman throughout her pregnancy, starting from before conception until two years after childbirth. The findings revealed significant alterations in the brain's structure and function, which are believed to be driven by the dramatic surges in hormones during pregnancy.

A Deep Dive into Pregnancy’s Impact on the Brain

The researchers took 26 brain scans of the woman, who conceived through IVF, while also collecting concurrent blood samples to track hormone fluctuations. One of the most significant findings was a steady reduction in grey matter—the brain’s outer layer—throughout the pregnancy. Additionally, they found a temporary surge in neural connectivity, peaking towards the end of the second trimester.

"Pregnancy leads to an orchestrated transformation of the maternal brain, and we are now able to witness this process unfold in real time," explained Prof. Emily Jacobs, a leading researcher on the study from the University of California, Santa Barbara.

This study distinguishes itself from earlier research by showing that many neurological changes during pregnancy are temporary and can return to normal by the time of childbirth. Earlier studies only provided snapshots of women’s brains at different stages of pregnancy, potentially missing these transient changes.

Writing in the journal Nature Neuroscience, lead author Laura Pritschet and her colleagues highlight how key pregnancy hormones, including estrogen and progesterone, bring about major physiological changes. These hormones affect not only the brain but also processes like blood plasma volume, metabolism, oxygen consumption, and immune system activity. Their influence extends into the brain, reshaping its structure.

Detailed Brain Scans Offer Fresh Insights

The precision MRI scans were performed on Dr. Elizabeth Chrastil, a colleague from the University of California, Irvine. The scans captured her brain before pregnancy, during gestation, and up to two years after her son was born in May 2020.

Reflecting on her experience, Chrastil shared: “It was quite an intense undertaking, but personally, I didn’t feel much different during pregnancy. Some people talk about experiencing ‘pregnancy brain,’ but I didn’t notice any such changes.”

The scans revealed various alterations, such as reduced grey matter volume and thickness in areas related to social cognition. White matter, which helps in the brain's communication, peaked during the second trimester before reducing. The scans also showed that cerebrospinal fluid and brain ventricles expanded during pregnancy, all of which were closely tied to the rising hormone levels.

“Some people might be alarmed when they hear that grey matter decreases during pregnancy, but this probably represents a fine-tuning of the brain's circuits," said Prof. Jacobs. She likened the process to the way Michelangelo sculpted the statue of David from a marble block.

Ongoing Research and Future Implications

While the research presents a clearer picture of how the brain changes during pregnancy, it doesn’t yet explain certain behaviors or emotional shifts commonly reported during pregnancy. According to the researchers, factors such as stress and sleep deprivation also contribute to these changes. What’s more, some brain alterations persisted two years after childbirth, suggesting that pregnancy could lead to lasting cellular changes in the brain.

“This paper raises more questions than it answers,” Dr. Chrastil noted. “We are really just beginning to understand the complexities of the maternal brain.”

The research marks the start of the Maternal Brain Project, an international initiative aiming to gather more brain scans from pregnant women. The project will further explore the neurological impact of pregnancy, including risks of postnatal depression and the effects of pregnancy on chronic conditions like migraines and multiple sclerosis.

Prof. Jacobs stressed the importance of studying the neurobiology of pregnancy: “There’s still so much we don’t know about pregnancy’s effects on the brain, and it’s not because it’s too complex to study. It’s because historically, women’s health has been largely overlooked by biomedical sciences.”

Gina Rippon, a cognitive neuro-imaging professor at Aston University, described the project as "truly heroic." She added: “The data from this study clearly shows how much information we’ve been missing when it comes to pregnancy and the brain.”

Reference:

1. Sample, I. (2024, September 16). Scans capture sweeping reorganisation of brain in pregnancy. The Guardian. https://www.theguardian.com/science/2024/sep/16/scans-capture-sweeping-reorganisation-of-brain-in-pregnancy

(Input from various sources)

(Rehash/Yash Kamble/MSM)