Mothers-to-be who blame brain fades on the fact they're pregnant aren't making it up, new research has found.
'Baby brain' is a real phenomenon, researchers at Deakin University in Australia have found.
PhD candidate Sasha Davies and colleagues looked at 20 previous studies that measured women's cognitive abilities, including more than 700 pregnant women, and found there was a statistically significant decline.
"General cognitive functioning, memory, and executive functioning were significantly reduced," their study, published in the Medical Journal of Australia, found.
But if she's hardly showing, be sceptical - the effect only kicks in during the third trimester.
And even then, the researchers warn against blaming a woman's mistakes at work on her baby.
"Small reductions in performance... 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).
"More significant consequences (eg. reduced job performance or impaired ability to navigate complex tasks) are less likely."
It's believed to be the result of a reduced amount of grey matter - a key part of the brain and central nervous system.