Studies on this turn up mixed results, at best.

Some studies on changes to working memory during pregnancy do show a small effect on the brain, though other studies show no negative impacts whatsoever.

There's actually growing evidence that being pregnant makes women more organized and smarter, at least, according to a study on rats.

It makes sense, though, since pregnant women and new mothers have a lot more to worry about and think about — for their brains to keep up they may even be getting a boost.