Skip to main content Interview with:
Dr. Liron Rozenkrantz
Postdoctoral Fellow
Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology
Program in Placebo Studies, Harvard Medical School
Former PhD student at Human Olfaction Research group, Department of Neurobiology
Weizmann Institute of Science

Reut Weissgross
Research student
Human Olfaction Research group, Department of Neurobiology
Weizmann Institute of Science What is the background for this study?

Response: A pregnancy loss is not such a rare event as you would think: it is estimated that about 50% of all conceptions (or 15% of the documented pregnancies) end in spontaneous miscarriage. About 1-2% of all couples trying to conceive will experience recurrent pregnancy loss (RPL), meaning 2-3 consecutive miscarriages, and despite going through numerous clinical investigations (hormonal tests, genetics and so) – about half of these cases will remain unexplained. This devastating phenomenon leaves couples with no explanation as to why they cannot bear a child. While most research in this field is focused on the reproductive organs (mainly the uterus), hormones and genes, we set out to look for new possible routes.

The literature regarding the tight connection between olfaction and reproduction, mainly by social body-odors (or pheromones), is heavily documented, especially in rodents. Body-odors emitted from males affect pubertal development of juvenile female rodents and estrus cycle, and females body odors affect other females’ fertility state. The most robust phenomenon in this relation is the Bruce effect, in which pregnant female mice who are exposed to body-odors from a non-stud male – will experience impanation failure in 80% of exposures! Since there is growing evidence for the involvement of the olfactory system in human reproduction, we asked whether the olfactory system is also involved in human reproductive disorders such as unexplained recurrent pregnancy loss (uRPL).

To answer this question, we recruited 40 women experiencing uRPL and 57 matched controls (who never experienced a miscarriage, and are at similar age to the uRPL women), and compared their olfactory profile, mainly in response to men’s body-odors. What are the main findings?

Response: In the first experiment, we tested whether the two groups can actually identify their spouse’s body odor among other men. The women were asked to smell 3 jars containing t-shirts worn by their spouse, a non-spouse man, and a blank t-shirt (not worn by anyone), and identify their spouse by smell only. While the control group did not succeed to identify their spouse by smell better than chance, the uRPL group performed significantly above chance, and as much as two-fold better than the controls.

When asked to rate these jars for the Intensity of the odor, its pleasantness, how much they are sexually attracted to the man possess this odor, and how much they think he is fertile. The uRPL group rated significantly different the odor of the non-spouse man in comparison to the control group, again indicating an altered response to men’s body odors.

We then tested whether this was because the uRPL women have simply a better sense of smell altogether. The women went through a battery of standard general olfactory abilities, in which we found they have only marginal better olfactory abilities in relation to everyday (and not body-odor-related) odors. Taking together the above experiments, the uRPL group displayed strikingly altered olfactory responses to men’s body odors, but less so in terms of ordinary (non-social) odors.

Lastly, we wanted to test whether these olfactory differences are evident in the anatomy and function of their brains’ olfactory system. We performed both anatomical and functional MRI scans. In the anatomical scans, we measured their volume of their olfactory bulbs- the first station of the olfactory system in the brain – and discovered they have significantly smaller olfactory bulbs. This was surprising, since better olfactory abilities typically correlate with bigger olfactory bulbs.

In the functional scans, we focused on the hypothalamus, the primary brain structure implicated in linking the brain’s olfactory and reproductive systems, and is responsible to regulate hormonal reactions, including pregnancy related hormones. We found a complete dissociation between the two groups, whereby, in response to men’s body odors, the uRPL groups displayed increased activation of the hypothalamus, while the control group showed reduced activation. Is a clinical application feasible?

Response: Altogether, these findings provide compelling evidences for a connection between olfaction and reproduction in women experiencing unexplained repeated pregnancy loss. Since we obviously cannot expose pregnant women to men’s body-odors and see if they will miscarry, we cannot provide a causal explanation for how the olfactory system is related or involved in this phenomenon of repeated miscarriages, or is it vice-versa (experiencing repeated miscarriages affect these women’s olfaction and perception of men’s body odors). Therefore, we cannot conclude practical or clinical implications yet, and there is still long research ahead to explore and perform in this field. What should readers take away from your report?

Response: In spite of the above said, this is the first time to our knowledge that RPL is being studied in the brain. We do hope that our research will help shedding light into altered mechanisms leading to human pregnancy loss, and will encourage fertility experts to explore not only the reproductive system of women who experienced unexplained repeated pregnancy losses (mainly their uterus) but also search from brain mechanisms, and research the olfactory system as a possible guide to solve this mystery. What recommendations do you have for future research as a result of this study?

Response: Future research should, as we said, look for brain and olfactory mechanisms in women experiencing uRPL, but also- look at the other side of the relationship- the spouses, or maybe even the interaction between the two. Meaning, could there be something in men’s body-odors, or the specific interaction of these couples? In our relatively small cohort, we could not explore this question. We hope we opened a door for possible research directions which will help couples experiencing this devastating disorder. Is there anything else you would like to add? Any disclosures?

Response: This study was conducted in Noam Sobel’s lab at the department of Neurobiology at the Weizmann Institute of Science in Israel, in collaboration with Prof. Howard Carp, head of the RPL clinic at Sheba, Tel Hashomer Medical Center in Israel. The study was funded by a European Research Council AdG. grant #670798 (SocioSmell). We want to thank all research team, and especially our participants. No disclosures.


Liron Rozenkrantz, Reut Weissgross, Tali Weiss, Inbal Ravreby, Idan Frumin, Sagit Shushan, Lior Gorodisky, Netta Reshef, Yael Holzman, Liron Pinchover, Yaara Endevelt-Shapira, Eva Mishor, Timna Soroka, Maya Finkel, Liav Tagania, Aharon Ravia, Ofer Perl, Edna Furman-Haran, Howard Carp, Noam Sobel. Unexplained repeated pregnancy loss is associated with altered perceptual and brain responses to men’s body-odor. eLife, 2020; 9 DOI: 10.7554/eLife.55305

Source: | Circumstantial Link Between Women’s Response to Men’s Body Odor and Recurrent Miscarriage



Humans can ‘smell’ each other’s emotions | Livescience

This article discusses the profound importance of the sense of smell in human relationships and social interactions. Chrissi Kelly, who lost her sense of smell after a viral infection, founded…

Sniffing body odour is tested as an anxiety therapy | BBC News

IMAGE SOURCE,GETTY IMAGES Sniffing other people's body odour might be useful in therapy for social anxiety, say Swedish researchers who have started tests with volunteers. The scientists have been using…

Does body odor indicate illness? What your smell says about you

The physician and biologist Hanns Hatt, professor at the Ruhr University Bochum, has been on the trail of the riddle of smell for decades. He decoded the first human olfactory…

Horses show ability to discriminate between human odors of fear and joy |

An example of one of the mares using her left or right nostril to sniff the sample. Photo: Plotine Jardat Horses are able to discriminate between human odors produced in…

Study Suggests Body Odor Can Reveal if a Man Is Single or Not | New Scientist

Photo: macniak/Depositphotos From our health to compatibility, our scent can say a lot about us. According to a new study, women can actually detect whether a man is single or…

Women can sniff out single men as scent reveals if you’re married, scientists claim | The US Sun

SNIFFING your date may not be the first thing you do but a study claims that women can actually smell if a man is married. According to scientific research based in Australia,…

Inside The Connection Between Scent And Attraction | Glam

Dragana Gordic/Shutterstock They say love comes down to chemistry. There's an undeniable, unexplainable "je ne sais quoi" when you meet "the one." Fragrance experts and scientists now believe that the chemical…

Dogs can smell when humans are stressed, study suggests | CTV News

Undated photo of a dog smelling. (Blue Bird/Pexels) Megan Marple There's now scientific evidence shedding more light on one of Barkley's impressive skills in a long list of endearing traits:…

Body odor sniffing linked to higher sex drive: study | Vigour Times

Sex smells! Enjoying the stench of body odor might not just be a bizarre fetish: Those who like whiffing other people’s natural aroma may have a higher appetite for sex…

T-Shirt Study Shows Importance of Mom’s Smell to Bond With Baby | Consumer Healthday

The sound of mom's voice can soothe a fussy baby like nothing else, but now new research suggests that an infant is also calmed by the scent of its mother.…

Viruses can change your scent to make you more attractive to mosquitoes, new research in mice finds | The Conversation

Mosquito-borne diseases are estimated to cause over 1 million deaths a year. mrs/Moment via Getty Images Mosquitoes are the world’s deadliest animal. Over 1 million deaths per year are attributed to mosquito-borne diseases, including…

Your Nose Knows: New Science Suggests Scents Matter to Humans as Much as to Dogs | The Epoch Times

(Adam Griffith) The human nose is not usually considered an asset. Most humans are more concerned with how our noses look than how they function, unless, that is, we’re plagued with sinus…

Does Your Nose Help Pick Your Friends? | New York Times

Credit...Robert Kneschke/Alamy In a small study, researchers in an olfaction lab found that people who had an instant personal connection also had similarities in their body odors. Human beings maintain…

Baby’s Superpowered Scent Can Manipulate Parents’ Moods, Researchers Find | VOA News Why would the smell of a baby's head calm men but rile women? It may be another example of how we're more animal than we like to think. Source:…

Medieval Aphrodisiacs: Body Scented Bread Dough! | Ancient Origins

People in Europe in the Middle Ages boosted libidinal sexual intimacy through the use of medieval aphrodisiacs, some of which are truly bizarre. Dr. Eleanor Janega, a medieval historian based…

Newborn babies’ smell has opposite effects on parents – study | JPost

Mother with newborn baby in the nursing pillow. (photo credit: INGIMAGE) Parents of newborn infants invariably gush: “There’s nothing like the smell of my baby!” But this is no mere…

Why Someone’s Scent Can Be A Make Or Break Factor In Creating Connection | The Zoe Report

Scent & Attraction Psychology — Why They Are So Connected When it comes to attraction, a lot of factors come into play, from physical to mental. But there’s one crucial…

T-Shirt Study Shows Importance of Mom’s Smell to Bond With Baby | HealthDay

Adobe Stock MONDAY, Dec. 13, 2021 (HealthDay News) -- The sound of mom's voice can soothe a fussy baby like nothing else, but now new research suggests that an infant…

A human pheromone could affect aggression | Popular Science

We're just starting to understand how smell can change human behavior. Unsplash Scientists observed how people reacted to frustrating computer games in the presence and absence of the molecule, known…

Yes, dogs can ‘catch’ their owners’ emotions | National Geographic

A girl and her dog in Boone County, West Virginia.PHOTOGRAPH BY STACY KRANITZ A pile of recent studies show how canines pick up chemical and physiological cues from people that…

Is there a biological basis for instant attraction? | New York Post

Is there a biological basis for instant attraction? New finings in mice has revealed an instinctual preference for those with similar genes.Getty Images Scientists are getting closer to identifying a…

Your dog has a rich interior life it’s not telling you about |

Gossiping Malamutes (Getty Images) From conveying personal data via scents to using body language to "speak," dogs are secretly great communicators Dogs and humans have co-evolved to the point that…

Why single people smell different | BBC

(Image credit: Michal Bialozej) By William Park There is a wealth of psychological and biological information stored in our scent, but for some reason we choose to ignore it. King…

Is an irresistible human pheromone possible? | Whyy

(Sergio Mazurini /Big Stock Photo) This story is from The Pulse, a weekly health and science podcast. Researcher Jessica Gaby says it’s about time those who lack deep human connections in life start…

Dogs that detect seizures may be sniffing out the scent of human fear | New Scientist

Dogs may be able to recognise the “smell of fear” Description:Credit: plainpicture/Mölleken Dogs that can predict when their owners are going to have an epileptic seizure may be recognising the…

Honeybees Use Scent Maps to Keep Track of Their Queen | Discover Magazine

(Credit: Samo Trebizan/Shutterstock) Honeybees can find their way back to their queen using a sophisticated form of the telephone game. Even after foraging for hours, they can smell the pheromones…

Bees form scent-driven phone tree to pass along messages | EurekAlert! Science News

Honeybees play a scent-driven game of telephone to guide members of a colony back to their queen, according to a new study led by University of Colorado Boulder. The research,…

Vagina-scented face masks | Boing Boing

Photo: Cottonbro / Pexels Samantha Cole reports on a pandemic trend that's nothing to sniff at: vagina-scented face masks.For fetish item sellers, the pandemic is an opportunity for a new kind…

Love Is an Emotion That Dogs Can Smell – Bioesse Develops Groundbreaking Inhalation Technology That Uses Pet-Owners’ Scent to Virtually Eliminate Canine Anxiety Issues in Normal, Healthy Dogs | PR Newswire

My Pet–My Scent. Bioesse Technologies Bioesse ( recently announced that it had researched, developed and patented a product that could nearly eliminate the daily canine anxiety-related issues experienced by average,…

Roane Co. widow helps strangers cherish the memory of their lost loved ones | WBIR

Juanita Jackson sews 'Memory Bears' out of articles of clothing to give comfort to people grieving from the death of a loved one. ROANE COUNTY, Tenn. — In an exclusive…