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This has always stuck in my mind from a book I read – I think it was The Mists of Avalon (awesome book btw). In it, a pregnant woman swears she can smell moonbeams when she’s pregnant, and they make her feel sick. So today I’m wondering, does pregnancy improve your nose? Can you smell the moon?

Made of Cheese

Every time I write a post like this I feel like I have to remind everyone that I’m not pregnant. So for the record – no bun in this oven. Just a scholarly curiousity.

Plenty of pregnancy sites out there will tell you that women become more sensitive to smells when they’re pregnant. They say this also occurs during ovulation, and may be due to changes in hormone levels. It may be a factor in morning sickness, as an increased perception of bad smells might make them want to throw up.

Measures of Human Olfactory Perception During Pregnancy by E. Leslie Cameron (full text available for free here) took 60 pregnant women (20 in each trimester), 20 non-pregnant women, and 20 post-partem women and made them scratch and sniff. There were 40 different scratch and sniff cards, with smells including lemon, menthol, grass and turpentine. After scratching, the number of sniffs was recorded by the experimenter as a measure of sensitivity (more sensitive, less sniffing) and the participant had to identify what the smell was, and rate the intensity and pleasantness of the odour.

In addition, before starting the women rated their own sense of smell generally. The results concluded that “consistent with anecdotal reports, nearly two-thirds (61%) of pregnant women indicated that their sense of smell was higher during pregnancy.” Whoop-de-do. But here’s where it gets interesting.

“Although pregnant women rated their sense of smell to be significantly higher than control participants, they were not better at identifying odors.” That said, women in the first trimester did seem to be more sensitive sniffers, because they took less whiffs. Here’s the graph showing the results (the UPSIT score is the “Identify this Smell” test)

What’s really cool is that the women THINK they smell better now they are pregnant, but there’s not the evidence there to say that this is REALLY the case. Is it just that this test wasn’t sensitive enough to pick up the change in smell which seems so noticeable to the smeller, or do they just feel like things smell different now? Is there a change, and does it effect the nose or the brain? Science, alas, is yet to have an answer.

Smelling moonbeams seems a little far-fetched though. But if you’re curious on what the moon smells like, astronauts say it smells like burnt gunpowder. After a moonwalk the dust sticks to their clothes and they say it smells very strong (they’ve even, accidentally I’m sure, tasted some!) Once the dust gets back to Earth it doesn’t smell anymore. Weird, right?