Women’s bodies undergo enormous changes during pregnancy. After all, they grow an entirely new organ (the placenta). And an actual human being.
New research out this week suggests pregnancy also changes women’s brain structure in ways that potentially help prepare them for parenthood ― changes that last for up to two years.
Researchers tracked 25 women in Europe over the course of five years, as well as a group of women who never conceived. They scanned the women’s brains both before pregnancy and then again shortly after they gave birth, looking for potential changes in gray matter, the tissue that makes up of the central nervous system.
They found that during pregnancy, volume shrunk in parts of the brain that play a key role in processing social signals and understanding the perspectives of others.
It is unclear what those changes mean at a practical level, however, the findings suggest that gray matter shrinkage in specific parts of the brain may somehow affect women’s maternal instincts ― partly because women whose brains experienced the biggest changes also scored higher months later on a test measuring mom-baby emotional bonding.
In other words, the brain isn’t necessarily just losing volume; it may be engaged in a process of fine-tuning itself to prioritize certain skills in preparation for motherhood.
“We found preliminary indications that these [changes] may reflect some type of specialization that might help [moms-to-be] in this next stage of life,” study author Elseline Hoekzema, a senior neuroscientist at Leiden University in the Netherlands, told The Huffington Post in an e-mail. (The study was conducted while she was working at the Autonomous University of Barcelona.)
There are other life stages when brain volume tends to shrink, namely adolescence.
"Over the course of childhood, the volume of gray matter in the cortex increases and then declines," the National Institute of Mental Health explains. "A decline in volume is normal at this age and is in fact a necessary part of maturation."
There is also some evidence from the animal world to suggest the theory of pregnancy-related brain changes is not totally outrageous.
“In rodents, reproduction leads to improvements in spatial memory, finding food and catching prey, which are essential skills to promote offspring survival,” Hoekzema said. Human brains might be engaged in a similar adaptive process during pregnancy that helps women take care of human babies in human society.
Ultimately, the findings are still speculative, but do provide some of the first insights into how pregnancy can affect the human brain, said Hoekzema, who added that she is currently pregnant herself.
“We’re not at a stage where these findings have any practical implications regarding motherhood,” she explained. “These are just the first steps in unraveling what happens in the brain.”