Science Questions

Do pregnant women smell different?

Sun, 8th Nov 2009

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Yassef asked:

Is pregnancy is detectable by smell?


Chris -   I think that you could probably make a case.  What do you think, Oriane?  I think you can probably make a case that you could detect pregnancy on the basis of smell because, say mosquitoes, they could be aligned for women who are pregnant.  That could be for a number of reasons.  One of them is that women who are pregnant have a higher metabolic rate so they breathe more.

Oriane: -   They also have a higher temperature.

Chris: -   Yeah.

Oriane: -   Due to the high progesterone during pregnancy.

Chris: -   So it could be either of those things.

Oriane -   Yeah.

Chris: -   But if they’re having a higher temperature, they’re probable exuding more volatile chemicals so they probably where have a slight different smell signature.  The mosquitoes can definitely home in on them.  So I think probably you could train a dog in the same way that dogs can be trained to discriminate urine from people who have renal and bloody cancers, on the basis of the volatile chemicals that the cancer puts into the urine.  Dogs can pick that up.  I reckon you probably could train a dog, something with a very sensitive nose, on, say, a woman’s urine, or on a woman’s sweat in order to tell whether she’s pregnant on the basis of a slight shift in the metabolism of that pregnant person.

Helen -   An interesting form of sniffer dogs, definitely.


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Yasser asked the Naked Scientists: Dear Naked Scientists,   Greetings from the rainy summer season in Toronto, Canada! After watching part 1 of Torchwood's Children of Earth, it got me thinking whether or a human being could detect pregnancy through the sense of smell alone. If there is any truth to this, it could lie in the pheromones but if humans cannot detect if somebody is pregnant just smell, would another creature with a greater sense of smell be able to do so?   Best Regards, Yasser in Canada   P.S. Great Podcast, as always. What do you think? Yasser , Mon, 3rd Aug 2009

This seems like the wrong forum for your question... Perhaps you should consider asking a moderator to move it. Stefanb, Tue, 11th Aug 2009

Sounds like it could require some technology to me!

I'd say that it's almost certain that the spectrum of exhaled or evolved volatiles from a woman could be used to determine her pregnancy status. Mosquitoes can definitely do this and, in fact, make a beeline (if that's the right word) to feed on pregnant women. They're therefore sensitive to the chemicals emitted by pregnant people; hence it doesn't seem so unlikely that a device would be made to register the exhaled agents, or skin-evolved chemicals, and determine a combination that is a sensitive and specific predictor of pregnancy.

Chris chris, Tue, 11th Aug 2009

I remember reading that there many studies going on of what mosquitoes can detect and are attracted by, and that within a few years it is exepected that the perfect repellent will be manufacturable. This is good, because although not pregnant (as a male in fact), I find that I am particularly attractive to mosquitoes.

Isn't it also true that it has been found that dogs can be trained to sniff out when someone has certain diseases and I also remember seeing that even some GPs reckon that smell is a good diagnostic aid. graham.d, Tue, 11th Aug 2009

That is really interesting question..So being mother to three children, I did not know that we breath out any particular odors while pregnant.. That is fascinating! Karen W., Tue, 11th Aug 2009

Once upon a time before being forced to spend hours in a post office equipment room and developing a paper dust allergy, I had a good  sense of smell most of the time with no sniffy non functions sometimes as today.

I had a co-worker I was assigned to mentor, she was just out of college, smart, qualified  but not experienced in the hands on bits of electronics or the company ways.
We`d been in the big brother little sister interaction model and had been mates for a year including going out to clubs. She had bought a serious leather jacket, and like all the bargain ones it stank.

One day she came in and whatever she was wearing worked with the jacket whiff pleasantly. Hmmm you smell nice today, what are you wearing? "Nothing, i overslept washed my hair no time to shower and came in to work" there was a look as If I`d said something really bad, so i kept clear, until later she sought me out and apologised, being a good Catholic girl she knew her cycles and she was on a peak fertility day and was rattled that she might be exuding to others too.

Recently I got clobbered ( again by a catholic woman) for simply the same , but she wore all sorts of expensive poncy musky stuff, and it was her out of the shower and dried off that smelled nice. "You make me feel like I`m  a bitch on heat"  Oh so you do like me them. Same  proximity to max fecundity part of period.

YES women do present complicated smells that men pick up on, but the levels are masked by perfume, and there is no message  other than hmm, she smells nice and a bit of enhanced interest.

We are all a lot less evolved than we pretend.
Edster, Tue, 18th Aug 2009

I found the opposite when it comes to mosquitoes.. while pregnant I didn't get bitten at all.. when I am not pregnant I am a mossie magnet.

JnA, Wed, 19th Aug 2009

Years ago I read an article about a new forensic technique that involved smell. The theory was that since we all had a unique smell, one could be pinpointed through smell alone. Of course the technique obviously had major flaws.. but the technology certainly exists to capture and analyse human smells.

Another thought that crossed my mind is that when 'newly' pregnant a woman's eating habits tend to change (either due to morning sickness or cravings or whatever) this could be a cause of a change in smell.

Sometimes you hear of mothers saying "I knew she was pregnant, I just knew it" do they know their daughter so well that they can pick up on subtle physical clues.. or are they smelling a change? JnA, Wed, 19th Aug 2009

Look, I don't care if he has got a good sense of smell, he ain't getting the position of consultant gynaecologist at this hospital! Don_1, Wed, 19th Aug 2009

First you must consider what is the standard odor of a non-pregnant woman.

That being said, a movie came through town a few weeks ago (disremember the name) in which during the opening scene the young husband remarks that she has suddenly begun to taste differently...uh, oh!

So the question may reduce to how well one is able to smell. MartinTheK, Thu, 20th Aug 2009

The alleged McClintock effect may be an example female hormonal state being detectable by smell. RD, Thu, 20th Aug 2009

Y'old "wolf is good at that", i'd like to find some dog trainers attempt that alike choosing colour tests.

(NOTE: dogs do not see in black and white, they see in Cyan and Yellow band frequency, Smell is a natural extra hyper-sensitive ability.
) nicephotog, Fri, 21st Aug 2009

Pregnancy is detectable by smell but only after 9 months has passed. After that time, the house in which the pregnant woman resides is filled with a variety of different yet pungent smells, that will unmistakably confirm the original speculation  Variola, Fri, 21st Aug 2009

My boss knew I was pregnant before I had told a single person other than the father who also had not told anyone. This was within two days of taking a pregnancy test... I thought this was so strange. My boss said, and his wife confirmed, that he knew she was pregnant before she knew. I am now 14 weeks, and I do think I smell differently. It is similar to an odor I have right before I have my period, but slightly different and stronger. olivia, Thu, 26th Apr 2012

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