We know that pregnancy completely changes the mother's body, but new research shows that the changes in the brain are just as fundamental.
Based on brain scans of a 38-year-old woman, performed over two years, scientists have managed to create the first comprehensive "map" of changes in the brain during pregnancy.
The data, published in the specialized journal "Nature Neuroscience", show a dynamic reorganization in the mother's brain, with the changes occurring like clockwork throughout the pregnancy.
How pregnancy rearranges the female brain
Changes in function and anatomy are registered in almost all parts of the brain, including in the areas involved in processing social and emotional connections, influences and interactions. Moreover, some of these changes remain visible for up to two years after the baby's birth.
Thus, scientists conclude that hormonal changes during pregnancy and motherhood reorganize the anatomy and function of the brain on a scale similar to those during puberty. "We were finally able to observe this change in real time," says study leader Emily Jacobs of the University of California, Santa Barbara, USA.
The brain being monitored belongs to Elizabeth Hrastil, who is also a neuroscientist. The scientists examined her brain using magnetic resonance imaging (MRI) every few weeks, with observations starting even before pregnancy and continuing for two years after birth.
The researchers recorded large-scale changes in the overall neuroanatomy of the brain that unfolded week by week during pregnancy. For example, changes occurred in gray matter volume, cortical thickness, white matter microstructure and ventricular volume.
"The results are remarkable. "They show that in a relatively short time, pregnancy can change the brain as much as puberty, for example," says American neurologist Claire McCormack, who was not involved in the study.
Figuratively speaking, white matter is a kind of pathway along which information is transmitted between different areas of the brain. The stronger these pathways are, the more efficiently the information is transmitted. This is exactly what scientists observed in brain scans during the pregnancy of neurologist Elizabeth Hrastil.
The observed changes affected the entire brain. "Over 80% of the areas of my brain showed a decrease in the volume of gray matter," says Hrastil herself. Gray matter is brain tissue with a high concentration of neuronal cell bodies. It is there that information is processed, which is why a decrease in the volume of gray matter is sometimes associated with a decrease in cognitive functions. However, the study authors explain that the reduction in gray matter during pregnancy is not necessarily something to worry about. Rather, it is a temporary specialization and even refinement of the brain as it prepares for motherhood - a bit like the process of sculpting a sculpture from a block of marble.
"This change in the brain likely reflects the fine-tuning of neural circuits. This adaptive process allows the brain to specialize," says study leader Emily Jacobs.
"We are only now getting a glimpse of this remarkable neurological process"
Studies are currently being prepared on many women to determine whether and how these brain changes affect the mother's psyche and health. The findings could improve our understanding of conditions such as postpartum depression and preeclampsia.
Shockingly, this is the first study to consistently map brain changes during pregnancy, the study authors write. "It is 2024, and we are only just getting a glimpse of this remarkable neurological process. There is so much about the neurobiology of pregnancy that we still don't understand. This is due in no small part to the fact that the biological sciences have historically neglected women's health," says Emily Jacobs. Of the 50,000 brain imaging papers published in the past 30 years, she estimates that less than one percent have focused on factors that affect women alone, such as pregnancy.
Author: Fred Schueller