Baby brain might be a real phenomenon, scientists say

A new study suggests there may be some truth in the belief that pregnancy makes women more forgetful.

Baby brain – an unofficial term used to describe the mental fog women say they experience during pregnancy – could be real, according to scientists.

A meta-analysis of 20 scientific studies suggests that cognitive deficiencies occurring during pregnancy – also known “mumnesia” – are measurable.

But researchers from Deakin University say the impact is likely to be noticed only by the women themselves and those closest to them.

Study author Dr Melissa Hayden said: “These small reductions in performance across their pregnancy will be noticeable to the pregnant women themselves and perhaps by those close to them, manifesting mainly as minor memory lapses (eg forgetting or failing to book medical appointments), but more significant consequences (eg reduced job performance or impaired ability to navigate complex tasks) are less likely.”

While forgetfulness is common among most people, many mothers-to-be say the small lapses of memory, such as struggling with names, misplacing things or forgetting what they are looking for, appear to be slightly more heightened during pregnancy.

Pregnant woman
Scientists believe the “baby brain” phenomenon might be real (Andrew Matthews/Getty Images)

Previous research, including a study carried out by the Massachusetts Institute of Technology in 2008, found a combination of fatigue, hormonal changes and stress can contribute to baby brain.

Another study analysing brain scans, published in Nature Communications in 2016, demonstrated pregnancy to cause a physical reduction in grey matter in the brain.

Study author Linda Byrne told the Australian Broadcasting Corporation: “It looks like the reason pregnant women have grey matter reduction is because they’re probably recruiting those areas to more important areas associated with the business of child rearing – so things like bonding, and social cognition.”

The current research analysed 1,230 women, 709 of whom were pregnant while the rest belonged to a control group.

Overall, the researchers found, cognitive function was poorer in pregnant women compared with women who weren’t pregnant.

The authors wrote in their paper: “General cognitive functioning, memory, and executive functioning were significantly reduced during the third trimester of pregnancy (compared with control women), but not during the first two trimesters.

Brain scans.
Brain scans have previously shown a reduction in grey matter among pregnant women (Jochen Sand/Getty Images)

“Longitudinal studies found declines between the first and second trimesters in general cognitive functioning and memory, but not between the second and third trimesters.”

They also found the signs of mumnesia appear during the first trimester.

The team added: “The differences primarily develop during the first trimester, and are consistent with recent findings of long-term reductions in brain grey matter volume during pregnancy.”

They said further research needs to be done to understand more about the effects of baby brain.

Byrne said: “These findings need to be interpreted with caution, particularly as the declines were statistically significant, but performance remained within the normal ranges of general cognitive functioning and memory.”

The research is published in the Medical Journal of Australia.

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