Pregnant women are as alert as they were before becoming pregnant. The so-called baby brain effect is no more than a myth, it has been found. It is a popular belief that pregnancy and motherhood affects a woman's memory, causing them to become more forgetful and absentminded.
Researchers at the Australian National University (ANU) say they have evidence pregnant women perform just as well in cognitive testing as they did before becoming pregnant.
The research team, led by Professor Helen Christensen of the Centre for Mental Health Research at ANU, recruited 1,241 women aged 20-24 and assessed their cognitive functioning. Four areas of cognition were assessed: cognitive speed, working memory, and immediate and delayed recall. The group of women were followed up at four-year intervals in 2003 and 2007 and given the same cognitive tests.
The researchers found no significant differences in cognitive change for those women who were pregnant during the assessments and those who were not. In addition, there were no significant differences between those women who had become mothers and those who had not. This led them to conclude that neither pregnancy nor motherhood have a detrimental effect on women's cognitive capacity - a finding that directly contradicts previous studies.
The researchers suggest that previous studies may be biased, either because they recruited women who were already anxious about the effect of pregnancy on their memory, or who were more depressed or sleep deprived. Additionally, this study recruited women prior to pregnancy, so cognitive function had already been tested before they became parents or mothers.
"Not so long ago, pregnancy was 'confinement' and motherhood meant the end of career aspirations. Our results show that mothers are the intellectual equal of their contemporaries," said Professor Christensen.
"Women and their partners need to be less automatic in their willingness to attribute common memory lapses to a growing or new baby. And obstetricians, family doctors and midwives may need to use the findings from this study to promote the fact that 'placenta brain' is not inevitable.
Professor Christensen added that mothers are primed to look out for signs of 'baby brain': "Part of the problem is that pregnancy manuals tell women they are likely to experience memory and concentration problems, so women and their partners are primed to attribute any memory lapse to the 'hard to miss' physical sign of pregnancy," she said. The study, 'Cognition in pregnancy and motherhood: prospective cohort study', is published in the British Journal of Psychiatry
Professor Helen Christensen says it is an idea she can relate to from personal experience.
"I've had three children myself and I do think about the literature I read at the time which was suggesting negative things that were going to happen to me," she said.
"When you are pregnant it's very salient, you can always blame something on pregnancy.
"If you forget your keys you just go 'oh gosh it's because I'm pregnant'."
Professor Christensen says studies of other species, including rats, have suggested the common beliefs could be wrong.
"Pregnant rats actually get better at performing spatial tasks compared to non-pregnant rats and they are also much better at managing their anxiety and their fear levels," she said.
Professor Christensen says while there was no evidence humans become smarter during pregnancy, there was no sign of deterioration either.