When mothers-to-be lose their keys or forget their phone, it is easy to blame it on "baby brain".
But it seems pregnant women may have to find another excuse for forgetfulness.
Scientists say that far from making women more absent-minded, pregnancy may actually make them brainier.
A study found expectant mothers do just as well on memory tests as other women - and in many cases, they actually do better.
The Canadian researchers say that far from turning the brain into mush, pregnancy may super-charge the grey matter, to help prepare women for the challenges of motherhood.
The team from the University of Western Ontario put 54 women through a battery of mental tests. The volunteers were all of a similar age and background but half were pregnant and half were childless. They found that both groups of women performed equally well on the tests.
And when the pregnant women who showed signs of depression were removed from the calculations, the mothers-to-be actually did better than their childless counterpart on tests of working memory.
We use this every day to hold one thing in mind while doing something else - such as remembering a phone number while looking for a pen and paper.
Researcher Elizabeth Hampson said when a woman isn't depressed, pregnancy hormones may tweak the brain's chemistry to improve memory. She said this would fit in with the idea that the brain rewires itself during pregnancy to prepare for the mental juggling that lies ahead as a new mother.
Writing in the journal Hormones and Behavior, she said the boost may persist into motherhood, although further work is needed to confirm this.
Dr Hampson, an expert on how sex hormones affect the brain, said that her results are "good news for women".
Earlier this year, a separate US study also concluded that "baby brain" doesn't exist.
Pregnant women did just as well as childless ones in a range of tests - however, they thought they'd done worse.
The Brigham Young University researchers said the expectation of problems may be so strong that a pregnant woman is simply extra-alert to any memory lapses.
- Daily Mail