Pregnancy changes the brain
PREGNANCY changes a woman’s brain, altering the size and structure of areas involved in perceiving the feelings and perspectives of others, according to a firstof-its-kind study published on Monday.
Most of these changes remained two years after giving birth, at least into the babies’ toddler years. And the more pronounced the brain changes, the higher mothers scored on a measure of emotional attachment to their babies.
“Just fascinating,” said Dr Ronald E Dahl, director of the Institute of Human Development at the University of California, Berkeley, who was not involved in the study, published in the journal Nature Neuroscience. He said the interpretation that changes in the brain enhance women’s maternal responses is “provocative, and I think it’s likely to be true”.
In the study, researchers scanned the brains of women who had never conceived before, and again after they gave birth for the first time. The results were remarkable: loss of grey matter in several brain areas involved in a process called social cognition or “theory of mind”, the ability to register and consider how other people perceive things. What might the loss mean? There are three possibilities, said Paul Thompson, a neuroscientist at the University of Southern California who was not involved in the study. “The most intuitive is that losing gray matter is not beneficial, that later on there may be negative consequences.”
Or, he said, it could be just a “neutral” reflection of pregnancy-related “stress, diet, lack of sleep”.
A third possibility is that the loss is “part of the brain’s program for dealing with the future”, he said. Hormone surges in pregnancy might cause “pruning or cellular adaptation that is helpful”, he said, streamlining certain brain areas to be more efficient at mothering skills “from nurturing to extra vigilance to teaching”.
The study strongly leans towards the third possibility.
“We certainly don’t want to put a message out there on the lines of ‘pregnancy makes you lose your brain’, as we don’t believe this is the case,” said Elseline Hoekzema, a researcher at Leiden University in the Netherlands, who led the study at the Universitat Autonoma de Barcelona in Spain. “Grey matter volume loss does not necessarily represent a bad thing,” she said. “It can also represent a beneficial process of maturation or specialisation.”
Pregnancy, she explained, may help a woman’s brain specialise in “a mother’s ability to recognise the needs of her infant, to recognise social threats or to promote mother-infant bonding”.
Researchers wanted to see if the women’s brain changes affected anything related to mothering. They found that relevant brain regions in mothers showed more activity when women looked at photos of their own babies than with photos of other children.
Experts said more research was required, involving more women and clearer assessments of social cognition to substantiate whether grey matter loss is truly linked to “theory of mind” and improved mothering skills.
Hoekzema is continuing the research, including in one very personal way. “I was pregnant with my first child when analyzing these data, but unfortunately I couldn’t get the before and after MRI scans of my first pregnancy,” she said.
Now, she is 20 weeks pregnant, with her second child. “Yes, I’ve certainly scanned myself before getting pregnant,” she said, “and will go into the scanner again after birth!”