Any woman who has had a child knows what "baby brain" is. Pregnant women are often forgetful and have trouble concentrating and this is often chalked up to the demands of pregnancy on the body. There've never been any conclusive findings into what, precisely, causes cognitive impairment in pregnancy, but recent research in Australia reveals that it's not an old wives tale, but a real syndrome that impacts four out of five women during their pregnancies.
Researchers at Deakin University in Victoria, Australia wanted to get the facts straight on baby brain and did a meta-analysis of 20 studies on pregnancy and cognition. There's a lot of research on the phenomena of forgetting things, being less attentive and focused during pregnancy, but not many of them agree. One study found that pregnant women actually have less grey matter and this decrease can be seen in MRI scans. Other studies attribute any mental fogginess to general fatigue that is common in pregnancy rather than any actual changes in brain function or structure.
The studies analyzed by the team at Deakin included a total of 709 pregnant women and 521non-pregnant women. When looking at cognitive assessments, those women who were pregnant did score lower than women who were not pregnant. The tests were specific to memory and executive function. Since executive function involves staying attentive and on task and making appropriate decisions based on input from the environment, it's important to understand if it varies during pregnancy. The team found that it definitely does, but not to the degree that puts women at risk of not being competent.
Deakin Ph.D. candidate Sasha Davies, one of the study co-authors, explained, "it's important to note that while we found differences, the pregnant women were still broadly performing in the normal range, albeit at the lower end, particularly for memory tasks. So while some pregnant women may notice they don't feel as "sharp" as usual, these effects are realistically not likely to have any dramatic impact on everyday life."
Timing was a factor as well. In some of the studies when cognitive function was measured at different points over the course of an entire pregnancy, the differences in mental acuity tended to start in the first trimester and were most noticeable in the third trimester. There was no way for this study to determine the exact cause of a drop in cognitive skills during pregnancy, but factors like hormone fluctuations, especially estrogen, progesterone, and oxytocin are likely part of it, as well as fatigue, stress and even morning sickness.
Dr. Linda Byrne, a professor in Deakin's School of Psychology cautioned that the results should be construed as evidence that pregnant women are not up to the tasks of their daily lives, stating, "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." So while "momnesia" is a real thing, it's not something that should cause anything more than minor adjustments to help remain focused, like reminder apps on a smartphone or asking friends and family to pitch in with help so mothers can rest more and stress less.