Pregnancy causes changes to brain structure that may allow mothers to adapt to care for babies, according to new research.
There was no suggestion in the study that pregnancy caused cognitive deficits or impacted memory function, partially debunking the oft referred to ‘baby brain’ accusations pointed at pregnant women. Quite the opposite. The results showed a neurological evolution whereby synapses are pruned to allow for greater empathy and understanding towards an infant - significant changes had in fact occurred in "brain areas associated with functions necessary to manage the challenges of motherhood".
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It’s the first time a clinical study has looked at the brain structure of women before and after a pregnancy, tracking any changes over a period of more than five years in total. The team, led by Òscar Vilarroya from the University of Barcelona (UAB), found a symmetrical reduction in grey matter in the medial frontal and posterior cortex line, and in some areas of the prefrontal and temporal cortex. These areas overlapped with regions of the brain related to empathy, which were activated while the mothers looked at images of their babies.
"These areas correspond to a great extent with a network associated with processes involved in social cognition and self-focused processing", explained Susanna Carmona, a former UAB researchers and co-director of the study.
Rather than the scans indicating the women were losing brain cells, Elseline Hoekzema, co-lead author on a paper published in Nature Neuroscience on the study, believes it is a sign of “synaptic pruning”.
“These changes may reflect, at least in part, a mechanism of synaptic pruning, which also takes place in adolescence, where weak synapses are eliminated giving way to more efficient and specialized neural networks," she wrote.
The team compared MRI scans of 25 first-time mothers and 19 male partners, with scans from 20 women who had never had a baby or been pregnant, and 17 male partners. There were no changes to the men’s grey matter, but it’s not clear whether that is a result of biology or time spent with the infant. The authors found it was incredibly straightforward, however, to identify whether a candidate had been pregnant or not, based on the reduction of grey matter in areas linked to social cognition.
"The findings point to an adaptive process related to the benefits of better detecting the needs of the child, such as identifying the newborn's emotional state," wrote Vilarroya. "Moreover, they provide primary clues regarding the neural basis of motherhood, perinatal mental health and brain plasticity in general."
The authors know the changes last at least two years after birth, but will need to study more women and for a greater length of time to see if the changes are ultimately transient and linked to hormone levels.
This article was originally published by WIRED UK
