Pregnancy changes brain structure: study

Sarah Wiedersehn
(Australian Associated Press)


Pregnancy leads to structural changes in the brain that persist for at least two years, according to a small study of first-time mums.

The changes, reported in medical journal Nature Neuroscience, result in a reduction of grey matter in areas of the brain responsible for social cognition – that is thoughts, feelings and intents towards other people.

The authors suggest this might prepare a woman for the social demands of imminent motherhood.

Pregnancy involves radical hormone surges and biological adaptations, however the effects of pregnancy on the human brain are virtually unknown.

Researchers at Leiden University, Netherlands, led by Eseline Hoekzema examined 25 first-time mother both before and after pregnancy to characterise pregnancy-induced structural changes in their brains’ grey matter.

Compared to the brains of 19 first-time fathers, 17 men without children and 20 women who had never given birth, first-time mothers exhibited reduced grey matter in regions associated with theory of mind.

The theory of mind relates to a person’s ability to attribute their beliefs, intents, desires and knowledge to oneself and others and to understand that others have beliefs, desires, intentions, and perspectives that are different from one’s own.

The researchers were also able to predict the quality of a mothers’ attachment to their own infants by observing, through the use of fMRI, these structural changes in the brain that persisted for two years after the birth of the woman’s first child.

Neural activity increased in some of these pregnancy-modified brain regions whey they showed mothers pictures of their own infants, relative to images of other babies.

‘Baby brain’ is a myth that has long been blamed for the memory loss many women report during pregnancy.

But while changes in brain structures associated with pregnancy were shown in this study, the authors note that they did not show actual cognitive deficits or memory problems, just simply that the area of the brain linked with these skills does change.

“In the current study, we observed no significant changes in memory performance in the women who underwent pregnancy between sessions in comparison to women who did not,” the authors wrote.


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