Many pregnant women report a decline in their cognitive abilities during pregnancy, but some studies have questioned such a phenomenon. New research tries to settle the controversy.

A huge number of pregnant women report such cognitive problems as trouble focusing and remembering things, confusion, reading difficulties, and forgetfulness.

Collectively, these symptoms are known as the "baby brain" phenomenon, or, more colloquially, "momnesia." According to an older and highly quoted study, between 50% and 80% of women say that they have experienced it.

Having baby brain can interfere with daily life; many women have reported that they were less verbally fluent and coherent at work, forgot appointments, or could not return to work at all due to these cognitive impairments.

Despite these accounts, some studies have argued that the baby brain phenomenon is nothing but a myth. Even though memory problems have been reported by a number of pregnant mothers, these are more likely to occur due to general tiredness than actual changes in brain function.

Other studies maintain that pregnancy changes the brain for up to 2 years, with reductions in the brain's gray matter being noticeable on a brain scanner.

So, to settle the dispute, researchers from Deakin University in Victoria, Australia, carried out a meta-analysis of 20 studies that reported a link between pregnancy and cognition.

The first author of the analysis is Sasha Davies, a PhD candidate at Deakin University, and the findings were published in the Medical Journal of Australia.

Reviewing 'baby brain' studies

The analysis performed by Davies and colleagues included a total of 709 pregnant women and 521 non-pregnant controls.

The studies examined general cognitive function, defined "as encompassing a range of processes, including memory, attention, executive functioning, processing speed, and verbal and visuospatial abilities."

They also analyzed memory, attention, and executive function—which refers to the ability to plan, move with flexibility from one idea to another, problem-solve, and the power of abstraction.

Davies and team found that "[g]eneral cognitive functioning, memory, and executive functioning were significantly poorer in pregnant than in control women, particularly during the third trimester."

"The differences primarily develop during the first trimester, and are consistent with recent findings of long-term reductions in brain gray matter volume during pregnancy," the authors write.

The cognitive declines were found "between the first and second trimesters in general cognitive functioning and memory, but not between the second and third trimesters," they explain.

Cognitive performance still normal

Davies and team call for further investigation into how these cognitive changes affect the daily lives of pregnant women, and they caution against a hasty interpretation of the results.

"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."

Study co-author, Linda Byrne

Study co-author, Dr. Melissa Hayden, also comments on the findings, saying, "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)."

However, she explains, "[M]ore significant consequences (eg, reduced job performance or impaired ability to navigate complex tasks) are less likely."