Tag: PLOS

Categories : OphthalmologyTags :

Proteins in Blood Could Help Predict Retinal Degeneration in Diabetics

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A model using 71 proteins associated with retinal degradation could predict risk in diabetics

Plasma proteomic signatures for early risk stratification of diabetic retinal neurodegeneration.
Credit: Wei Wang and Huangdong Li / Zhongshan Ophthalmic Center, Sun Yat-sen University (CC-BY 4.0, https://creativecommons.org/licenses/by/4.0/)

An AI-assisted model based on 71 different blood proteins could help doctors better predict retinal degeneration in diabetic patients before symptoms occur, according to a study published June 2nd in the open access journal PLOS Medicine by Huangdong Li from the Guangdong Provincial Clinical Research Center for Ocular Diseases in Guangzhou, China, and colleagues.

More than half a billion people around the world are now affected by diabetes. People with the disease are at risk of different neurodegenerative conditions, including the breakdown of the retina, the part of the eye that detects light, in a condition called diabetic retinal neurodegeneration (DRN). It can cause severe visual impairment and vision loss, and scientists believe that DRN is a “window” into the diabetic degeneration of other parts of the nervous system, including cognitive impairment and dementia, as well as degradation of nerves in peripheral areas like the fingers and toes.

Unfortunately, DRN is only detected after symptoms appear, when damage is already irreversible. To better predict who might suffer from DRN and when, the researchers sampled the blood plasma from 1492 patients in the Guangzhou Diabetic Eye Study with type 2 diabetes who did not yet have DRN, and examined the eyes of 1218 of them through scans over a six-year period. They compared their results with another 502 people with diabetes in the United Kingdom BioBank.

The researchers identified 71 different plasma proteins associated with DRN. The proteins were part of cell pathways for processes like inflammation and cellular maintenance. Using machine learning, the scientists used the protein levels in plasma to develop a predictive model called Pro-DRN which was able to improve on the best-performing model by 26 percent. The scientists have already put the model online to allow doctors to assess the risk. While Pro-DRN is based on plasma protein levels and relies on associations between protein levels and DRN and not direct causes, the authors hope that it could help doctors predict and potentially prevent neurodegeneration, using a simple blood test analysed by AI.

The authors add, “Our study suggests that early retinal nerve damage in diabetes leaves measurable signals in the blood. By combining plasma proteomics, longitudinal retinal imaging, and explainable AI, Pro-DRN may help move diabetic eye care from detecting established damage toward earlier, molecularly informed risk stratification, so that closer monitoring and future neuroprotective interventions can be directed to the people most likely to benefit.”

Provided by PLOS

Categories : Medical Research & Technology NeurologyTags :

Patient Cryopreservation Given a One in Four Chance of Working

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Opinions ranged widely, with some physicians concerned that preparation for preservation could interfere with best practices for a patient’s care.

AI image of a brain being cryogenically preserved. [Ed: The patient better have some hefty medical aid to pay for a new body in the year 3000…]

Surveyed US physicians believed preservation has a one in four chance of working, though opinions amongst physicians varied. Ariel Zeleznikow-Johnston of Monash University, Australia, and colleagues present their findings in the study, published on May 20, 2026 in the open-access journal PLOS One.

It’s unclear whether there is a consensus amongst doctors regarding preservation – the storing of bodies at extremely low temperatures, or using preservative chemicals, in the hopes of future revival. Preservation is not the only way in which physicians have to balance concerns about unproven treatments with patients’ preferences, but it is one with high stakes as it pertains to the end of someone’s life. The technologies necessary to revive someone have not yet been realised, though current preservation organisations report several hundred patients preserved globally, with thousands more signed up for future preservation.

In this study, Zeleznikow-Johnston and colleagues conducted a survey of over 300 physicians, nearly half of whom were primary care providers, the rest being various kinds of specialists including neurologists, intensive care doctors, anaesthesiologists, and doctors who specialise in palliative care. The survey was designed to address three main themes: the perceived feasibility of preservation procedures, clinical interventions that could improve preservation outcomes, and the ethical and legal standing of preservation as an end-of-life option.

About one in four of the physicians said they believed it was plausible, or even very plausible, that someone could be revived in the future after preservation. Just under half said it was unlikely. Neurosurgeons, on average, rated the possibility of revival highest, though most of the other specialties showed a wide spread of opinions that slanted more towards scepticism.

The way doctors are most likely to interact with preservation in their professional capacity is in the choices a patient may make for end-of-life care. A majority of physicians supported prescribing anti-coagulants to dying patients, which could help with the quality of preservation. However, fewer respondents were comfortable with more extreme procedures, such as patients going through medically assisted death and opting to begin the preservation before cardiac arrest. The doctors who most commonly have conversations about end-of-life care were overall more supportive of this kind of choice. About one in five doctors were concerned that decisions to increase the odds of successful cryopreservation would clash with providing the best standards of care.

Currently, pre-cardiac arrest preservation in humans is, to the best of our knowledge, not legally permitted anywhere in the world, but if the technology develops further, may become an issue healthcare professionals must grapple with. The authors emphasise that clarifying the clinical, legal, and ethical frameworks for use of preservation as an end-of life procedure is important, and note that the speculative nature of the findings should be carefully considered.

Zeleznikow-Johnston adds: “A lot of physician hesitancy may come from simple unfamiliarity with the scientific basis of modern preservation methods. The doctors who have actually thought about this – and who regularly sit with dying patients – tend to be more receptive, not less.”

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Categories : Gastrointestinal NeurologyTags :

Head Impacts Associated with Altered Gut Microbiome in Football Players

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Non-concussive head impacts correlated with changes to the gut microbiome on following days, in pilot study tracking six US collegiate football players over one season

Image credit: Rich Barnes / Colgate Athletics, CC-BY 4.0 (https://creativecommons.org/licenses/by/4.0/)

Non-concussive head impacts – hits to the head that don’t cause clinically detectable symptoms – are correlated with subsequent changes to the gut microbiome in a small sample of US collegiate football players, according to a new study published May 6, 2026, in the open-access journal PLOS One by Ahmet Ay and Kenneth Douglas Belanger of Colgate University, USA, and colleagues.

Non-concussive head impacts are common in American football, with players experiencing between 100 and 1000 across a season. While research has shown that full concussions can disrupt the gut microbiome – which regulates inflammation and the neuroimmune system – whether sub-concussive hits might produce similar effects had not been investigated.

In the new study, researchers tracked six NCAA Division I American football players across a competition season, beginning during preseason training. Their on-field activity profiles were monitored using GPS units and head impacts were tracked using a helmet-based sensor system; 226 faecal samples were analysed for their microbiome composition; and participants completed lifestyle questionnaires after each sample collection.

The researchers found that microbial diversity changed within two to three days after a substantial head impact. Specifically, certain bacteria – including the order Coriobacteriales, the family Prevotellaceae, and the genus Prevotella – tended to decrease in abundance while the genus Ruminococcus increased. In previous studies, these changes have correlated with brain injury and inflammation.

The athletes’ gut microbiomes also changed significantly over the course of the season, with mathematical modelling suggesting that the cumulative effects of non-concussive head impacts was likely associated with this shift, even after accounting for 15 potentially confounding factors including diet changes, exercise intensity, sleep, and stress.

The study is limited by its small sample size and lack of a control group, with its design meaning findings could only establish correlation but not causation. However, the authors conclude that even sub-symptomatic head impacts might affect the gut microbiome, both in the immediate aftermath of injury and over a longer time course in athletes who experience multiple impacts. 

Ken Belanger adds: “As far as we are aware, this is the first study to examine connections between head impacts and the composition of the gut microbiome – the complex community of bacteria and other organisms within the digestive system.”

“Our results provide evidence that even head impacts that do not result in a concussion or other reported symptoms may influence the microbes present within the gut, both in the short- and longer-term. Determining what causes these changes and whether they have a positive or negative influence on recovery from head injury will require further investigation.”

“Our research highlights the importance of thinking integratively about the interactions between the gut and the brain. We are only beginning to scratch the surface in our understanding of how these complex organs and organ systems communicate with and affect each other.”

Aziz Zafar adds: “After having only heard of the complicated interplay between neuronal inflammation and the gut microbiome, I found it to be such an exciting scientific experience to explore that interplay in the context of head impacts.”

Zachary Pelland adds: “It has been an amazing privilege to work so deeply on a personally and scientifically meaningful project which could not have happened without immeasurable support across academic departments, athletics, administration, and alumni at Colgate University.” 

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Categories : Mental HealthTags :

People with Poor Mental Health Have Worse Healthcare Experiences

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Poorer mental health was associated with worse reported care and less trust in the healthcare system

Photo by Alex Green on Pexels

People with self-reported poorer mental health also report worse quality of care and lower confidence in healthcare systems, according to a study published May 5th in the open-access journal PLOS Medicine by Margaret E. Kruk from Washington University in St. Louis, U.S., and colleagues.

Rates of depression and anxiety have increased worldwide since the COVID-19 pandemic, and more people are pursuing mental health treatment as a result. However, there is limited up-to-date data describing how these individuals seek out and receive care. Detailed, population-level information can help healthcare systems meet this growing population’s needs.

To make a start on gathering this data, Kruk and her colleagues surveyed 32 419 adults in 18 high-, low-, and medium-income countries. More than 1000 people from each country responded. Participants self-reported data via the People’s Voice Survey in 2022 and 2023.

First, survey respondents self-assessed their physical and mental health (the latter including “poor,” “fair,” “good,” “very good,” and “excellent”). Then, they quantified their overall confidence in the healthcare system, their own use of healthcare services, the typical quality of care received, and their ability to manage their own mental health (a metric called patient activation).

Mental healthcare receipt among people with poor mental health. Infographic displaying the weighted distribution of mental health status and care receipt. Each figure icon represents 2% of the population. Dark orange = respondents with poor/fair mental health who received mental healthcare in the past 12 months; light orange = those with poor/fair mental health who did not receive care; blue = those with good/very good/excellent mental health.

Image credit: Kruk ME, et al., 2026, PLOS Medicine, CC-BY 4.0 (https://creativecommons.org/licenses/by/4.0/)

Across all countries, respondents reporting poor mental health were more likely to report chronic illness, poorer overall health, lower patient activation, worse care quality and lower confidence in the healthcare system. Between 0.9% (Lao PDR) and 52.4% (UK) of these respondents reported receiving mental health care in the last year. Respondents in Nigeria reported the best overall mental health (4.7% people reported the lowest proportion of “poor” or “fair” mental health (4.7%), while respondents in China had the highest proportion (39.6%).

The researchers hope these results can help the countries in question – and individual healthcare systems – better serve the needs of those with poor mental health. While this is a descriptive study, the researchers posit patient activation as a potential target for elevating overall health and wellness.

The authors acknowledge that big-picture data doesn’t describe individuals’ specific experiences within the healthcare system. They suggest comparison across similar health systems and tracking system performance over time to continuously improve health services.

The authors add, “What stands out from this study is that poor mental health doesn’t exist in isolation. People reporting poor mental health were nearly twice as likely to have a chronic illness and far less likely to feel empowered to manage their own health. Health systems need to stop treating mental health in a silo and recognise that these patients are showing up across all areas of care – and often with more complex needs.”

Kruk adds, “As a research consortium working across very different health systems, we expected to find variation, and we did, in treatment access. But the experience gap was remarkably consistent: people with poor mental health had worse care, more unmet needs, and less trust in the system, regardless of where they lived. Health systems globally need to rethink how they serve this growing group, not just whether they can reach them.”

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Categories : CancerTags :

Age, Sex, and Cancer Type Influence Risk of Subsequent Cancers Among Survivors

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Findings may have implications for long-term cancer survivorship surveillance

Researchers assess the risk of developing a subsequent primary cancer based on demographic factors and cancer characteristics. Tara Winstead, Pexels (CC0, https://creativecommons.org/publicdomain/zero/1.0/)

Risk of developing a subsequent primary cancer varied significantly by age at initial diagnosis, sex, and type of first cancer, according to a study by Oxana Palesh and Susan Hong and colleagues at Virginia Commonwealth University, U.S., published April 28th in the open-access journal PLOS Medicine.

Advances in cancer detection and treatment have led to a growing population of cancer survivors. In the U.S., the number of cancer survivors is expected to grow by 22% over the next decade – from 18 million in 2025 to more than 22 million by 2035. Survivors remain at higher risk for developing new primary cancers distinct from their original diagnosis. This risk may be influenced by factors such as older age, exposure to radiation and/or chemotherapy and ongoing lifestyle factors like smoking, obesity and poor diet. Understanding who is at greater risk and how this risk changes over time can help to inform prevention and monitoring strategies.

Using retrospective data from more than 3 million cancer survivors in the U.S., researchers examined how demographic factors and cancer characteristics correlate with subsequent cancer risk. Several factors were associated with developing a subsequent cancer, including older age at initial diagnosis and male sex. In addition, survivors of lung, bladder, and skin melanoma were at higher risk of developing new cancer.

These findings reinforce the importance of long‑term survivorship care and risk‑based monitoring. By identifying survivor groups at heightened risk, studies like this can help to inform tailored prevention strategies, surveillance guidelines, and survivorship care planning as the cancer survivor population continues to grow.

First author Hui Cheng adds, “By examining nearly five decades of national data, we found population-level shifts in subsequent primary cancer risk, with several survivor groups experiencing rising risks. These findings can help design more tailored surveillance and prevention strategies.”

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Categories : Cardiovascular DiseaseTags :

Genetic Study in Indians Finds New Pathways Involved in Cardiometabolic Disease

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Study of 3000 Punjabi Sikhs may yield new targets for treating Type 2 diabetes and other disorders

Photo by Sangharsh Lohakare on Unsplash

A study conducted in an Indian population has identified new molecular pathways that contribute to cardiovascular disease, which had not been reported previously in studies of Europeans. Dharambir Sanghera of the University of Oklahoma Health Sciences Center, US, led the new study, which was published April 23rd in the open access journal PLOS Medicine.

Worldwide, rates of cardiometabolic disease, which includes obesity, Type 2 diabetes and heart disease, are on the rise, and South Asian people living abroad appear to be especially susceptible. Previous studies have looked for genes that influence the levels of various breakdown products of lipids in the blood and their connection to different diseases, but most of this research has been conducted in people of European ancestry.

In the new study, researchers looked at how genetics influenced the levels of 516 lipid metabolites in the blood of 3000 Punjabi Sikh individuals, in an effort to better understand how these genetic pathways contribute to disease in different ethnic groups. They compared their findings to previous results from more than 1 million Europeans and 15 000 individuals with Indian ancestry. The team identified new genetic pathways that link specific lipid metabolites to disease. Notably, they confirmed that one metabolite, LPC O-16:0, which is known to be involved with immune cell signaling and inflammation, influences Type 2 diabetes risk. They also identified a genetic variant that may protect Indians from developing heart disease by modulating levels of the metabolite PC 38:4.

These findings offer new insights into the diverse molecular origins of cardiometabolic disease and provide potential pathways to be explored for designing innovative therapies. The researchers conclude that including more non-European participants in this type of research would help in identifying distinct disease subtypes linked to different genetic pathways. These advances would likely be beneficial in clinical practice by enabling more personalised therapies and preventive strategies for people from different backgrounds.

The authors add, “This study reveals new genetic pathways and lipid markers that contribute to type 2 diabetes and heart disease, specifically emphasising how immune system signaling affects metabolic health. By identifying unique genetic signatures in Asian Indians, the research advocates for ancestry-specific medical approaches to address chronic immuno-vascular conditions in cardiometabolic disease.”

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Categories : UncategorizedTags :

Neanderthals May Have Used Birch Tar for Its Anti-bacterial Properties

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Experiments confirm anti-biotic properties of birch bark extract

The bark of birch trees has been used to produce tar for more than 150 000 years. The centre photo shows birch bark tar condensed onto a rock that borders a hearth. When scraped off the rocks, the viscous tar can be used as both an adhesive and antibiotic.

Neanderthals probably used birch tar for multiple functions, including treating their wounds, according to a study published March 18, 2026 in the open-access journal PLOS One by a team of researchers led by Tjaark Siemssen of the University of Cologne, Germany, and the University of Oxford, UK.

Birch tar is commonly found at Neanderthal archaeological sites, and in some cases this tar is known to have been used as an adhesive to assemble tools. Recently, some researchers have raised the question of whether Neanderthals had multiple uses for this substance. For instance, Indigenous communities in northern Europe and Canada use birch tar to treat wounds, and there is growing evidence that Neanderthals also employed a variety of medical practices.

To investigate the medicinal potential of birch tar, Siemssen and colleagues extracted tar from modern birch tree bark, specifically targeting species known from Neanderthal sites. They used multiple extraction methods, including distillation of tar in a clay pit and condensation of tar against a stone surface, both of which would have been methods available to Neanderthals. When exposed to different strains of bacteria, all of the tar samples were found to be effective at hindering the growth of Staphylococcus bacteria known to cause wound infections.

These experiments not only support the efficacy of Indigenous medicinal practices, but also reinforce the possibility that Neanderthals used birch tar to treat wounds. The authors note that there are other potential uses of birch tar, such as insect repellent, as well as other plants to which Neanderthals had access. Further exploration of the multiple potential uses of these natural ingredients will enable a more thorough understanding of Neanderthal culture.

The authors add: “We found that the birch tar produced by Neanderthals and early humans had antibacterial properties. This has important implications for how Neanderthals may have mitigated disease burden during the last Ice Ages, and adds to a growing set of evidence on healthcare in these early human communities.”

“By bringing together research on indigenous pharmacology and experimental archaeology, we begin to understand the medicinal practices of our distant human ancestors and their closest cousins. Additionally, this study of ‘palaeopharmacology’ can contribute to the rediscovery of antibiotic remedies whilst we face an ever more pressing antimicrobial resistance crisis.”

“The messiness of birch tar production deserves a special mention. Every step of the production is a sensory experience in itself, and getting the tar off our hands after spending hours at the fire has been a challenge every time.”

Provided by PLOS

Press preview: https://plos.io/3P6QrS5

In your coverage, please use this URL to provide access to the freely available article in PLOS One: https://plos.io/4le9beh

Contact: Tjaark Siemssen, tjaark.siemssen@arch.ox.ac.uk

Image caption: The bark of birch trees has been used to produce tar for more than 150,000 years. The centre photo shows birch bark tar condensed onto a rock that borders a hearth. When scraped off the rocks, the viscous tar can be used as both an adhesive and antibiotic.

Image credit: Tjaark Siemssen, CC-BY 4.0 (https://creativecommons.org/licenses/by/4.0/)

High-resolution image link: https://plos.io/4cteLHD

Citation: Siemssen T, Oludare A, Schemmel M, Puschmann J, Bierenstiel M (2026) Antibacterial properties of experimentally produced birch tar and its medicinal affordances in the Pleistocene. PLoS One 21(3): e0343618. https://doi.org/10.1371/journal.pone.0343618

Author countries: U.K., Canada, Belgium, Germany

Funding: Tjaark Siemssen is funded by the Boise Trust of the University of Oxford and the German Academic Scholarship Foundation (Studienstiftung). Aderonke Oludare was funded by Canadian Institutes of Health Research (CIHR) Project Grant 420598 awarded to Matthias Bierenstiel. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Competing interests: The authors have declared that no competing interests exist.

Categories : ExerciseTags :

Urban and Rural Residents Engage in Different Kinds of Physical Activity

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In new study, rural and urban residents differed in the types of physical activity they do the most

Photo by Azat Satlykov on Unsplash

In a study of US adults, walking was, by far, the most popular leisure-time physical activity, while rural residents also enjoyed gardening, hunting and fishing, and urban residents more commonly reported running, weightlifting and dance. Urban residents were more likely than rural residents to meet physical activity guidelines. Christiaan Abildso of West Virginia University, US, and colleagues present these findings in the open-access journal PLOS One on April 1, 2026.

The US Department of Health and Human Services publishes guidelines on recommended amounts of aerobic and muscle-strengthening physical activity for adults. While the overall proportion of U.S. adults meeting these guidelines has increased in recent decades, certain populations are less likely to meet them, including adults living in rural areas. Understanding differences in preferred recreational physical activities could help inform efforts to reduce such disparities.

However, few studies have examined urban versus rural preferences for leisure-time physical activities, and how they relate to meeting guidelines. To address that gap, Abildso and colleagues analysed telephone survey data collected from a national sample of 396 261 U.S. adults in 2019.

Out of 75 survey options for leisure-time physical activities, walking was the most popular among both urban and rural adults, with 44.1% reporting walking as the activity they spent the most time doing. This finding echoes a similar study of U.S. data collected in 2011, which also found walking to be the top activity. However, further analysis of the 2019 data showed that even among walkers, only 25% met combined guidelines for aerobic and muscle-strengthening physical activity, and about 22% did not meet either guideline.

The popularity of other activities varied. For instance, rural residents reported higher rates of gardening, hunting, fishing, and farm work, while urban residents had higher participation in running, weightlifting, bicycling, and dance. However, in general, rural adults were more likely to be inactive and less likely to meet guidelines for aerobic or muscle-strengthening physical activity.

These findings could help inform efforts to boost physical activity by tailoring solutions to be more culturally and demographically appropriate. The researchers also call for a similar analysis of more recently collected data, as habits may have shifted during the COVID-19 pandemic.

Christiaan Abildso adds: “We expected to see that walking would continue to be the most common physical activity. However, it was surprising to see that nearly 1 in 4 adults who walk as their main activity did not meet either of the physical activity guidelines. That is, they reported less than the recommended 150 minutes per week of moderate-intensity aerobic activity and less than the recommended 2 days per week of muscle strengthening activity, such as yoga or exercises with resistance bands.”

“What we might be seeing in these rural-urban differences in preferences may just reflect what people have access to or what is culturally supported. In our work, we see a need to continue to support our partners in small towns and rural places by creating physical, social, and cultural conditions that support physical activity. This could mean creating a wide shoulder on a country road for running and cycling, helping a senior centre with their chair exercise programming, creating or improving park spaces, expanding the national network of rail-trails, renovating abandoned and dilapidated structures (Brownfields) into viable activity centres, keeping school facilities open to the public, and many other strategies. Everyone needs to ask, ‘how does what we’re doing affect physical activity,’ in order to help get people more active, more often, in more places.”

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Categories : Diet and NutritionTags :

Sugary Drink Taxes May Not Be Effective in Fast-food Settings

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Analysis of nearly 7 billion Taco Bell transactions finds sugary drink taxes not linked to lower beverage calorie purchases

Photo by Breakingpic on Pexels

Taxes on sugary drinks had no effect on beverage calorie purchases from fast-food chain restaurants in the U.S., according to a new study by Brian Elbel and Pasquale Rummo from NYU Grossman School of Medicine and colleagues publishing April 2nd in the open-access journal PLOS Medicine.

Sugary drink taxes have been adopted in several U.S. jurisdictions as a public health strategy to curb sugar consumption and improve dietary behaviors. Research on the impact of these taxes on grocery stores purchases attribute sugary drink taxes to an estimated 15% decrease in sales. However, whether this translates to an impact in restaurant sales has not been well studied.

Researchers analyzed six years of sales data (2015–2020) from more than 7,300 Taco Bell locations nationwide, focusing on drive‑through purchases. The study compared beverage calories per transaction at 60 restaurants across five jurisdictions with sugary drink taxes—Albany, California; Cook County, Illinois; Oakland, California; Philadelphia, Pennsylvania; and Seattle, Washington—with a matched group of similar restaurants in areas without such taxes.

Overall, the analysis found no significant association between sugary drink taxes and beverage calories per transaction, suggesting that sugary drink taxes of this size or alone may not substantially reduce beverage calorie consumption in fast food restaurant settings.

The authors note that consumer behaviour in restaurants—such as choosing combo meals or prioritising convenience—may limit the effectiveness of these policies.

Elbel adds, “Using millions of transactions from six years of sales data, we found that sugary beverage taxes did not influence beverage calories when implemented in five cities in the U.S.”

Rummo notes, “These results suggest that sugary drink taxes may not be effective in reducing beverage calorie consumption in fast food restaurants, as compared to supermarkets. This could be because the sizes of sugary drink taxes in the U.S. are too small for consumers or that they just aren’t responsive to price changes in these settings, among other reasons.”

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Categories : Obstetrics & GynaecologyTags :

Yawns in Healthy Foetuses Might Indicate Mild Distress

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Foetuses yawn in the womb, with more yawns associated with a lower weight at birth

Photo by Mart Production on Pexels

Even in the womb, where all oxygen is provided by the parental placenta, foetuses can – and do – yawn. More yawns during observation were associated with a lower weight at birth – potentially indicating mild foetal stress in the womb, according to a study published February 25, 2026 in the open-access journal PLOS One by Damiano Menin, of the Università degli Studi di Ferrara in Italy, and colleagues.

Yawning is a behaviour found across vertebrates – and no one quite knows why. In humans, foetuses yawn in the womb from about 11 weeks. Even though there is no air to breathe, they slowly open their mouths, make motions similar to inhalation and exhalation, and close their mouths again. To understand more about foetal yawns, the authors of this study used ultrasound to observe 32 healthy foetuses (56% female, 44% male) between 23 and 31 weeks. Each foetus was observed for 22.5 minutes.

The authors found that the foetuses yawned between zero and six times during the observation period, with an average of 3.63 yawns per hour. They also showed that foetuses that yawned more during their observations were more likely to have a low weight at birth, which is considered as an indicator of mild distress – though all foetuses in the study were born healthy.

The researchers did not perform any manipulations to see if they could affect foetal yawning and also did not record measures such as foetal heart rate or maternal temperature which might potentially be associated with the behaviour. Additionally, no high-risk pregnancies were observed. Based on their research, the authors suggest that frequent foetal yawning might be a sign of mild distress in the healthy foetus.

The authors add: “We found that yawning frequencies in the womb are negatively related to birth weight, potentially indicating a stress-related response in healthy fetuses. This suggests that even before birth, yawning may serve as an indicator of a foetus’s well-being.”

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