Girls whose mothers took paracetamol (acetaminophen) during pregnancy had smaller ovaries at three months old, on average, than those whose mothers didn’t take the drug, according to a study of about 300 infant girls in Denmark. Infant boys whose mothers took paracetamol had smaller testes on average too, the study found.

That doesn’t prove paracetamol caused the reduction in the average size of ovaries and testes, though – this association could be a result of the conditions that led to the women taking paracetamol during pregnancy, or even due to chance alone. Nor is it clear whether having smaller ovaries or testes as an infant affects fertility in adulthood. However, the findings are in line with separate studies done in rats and mice, in isolated human ovaries and in human embryonic cells.

“We still recommend that pregnant women should use paracetamol with high fever or strong pain,” says at Copenhagen University Hospital–Rigshospitalet. Not doing so can be risky, she says.

But most of the women in the study used paracetamol for headaches or musculoskeletal pain, rather than fevers, and could have managed their pain or discomfort in other ways, such as via rest, heat treatment or physiotherapy, says Fischer.

“We should have a dialogue about when paracetamol is actually necessary,” she says. “It is still a drug and it does have side effects. Maybe it shouldn’t be the first thing that we grab when we have discomfort.”

The issue is that there are almost no safe drug-based alternatives to paracetamol for pregnant women. Most other painkillers aren’t recommended because they can cause congenital conditions.

Fischer’s team recruited 685 pregnant women during their first trimester, who were asked about their use of medicines every two weeks. They had an fetal ultrasound during their third trimester, and 302 daughters were examined around three months after birth.

Those exposed to paracetamol as a fetus had, on average, 40 per cent smaller ovaries by volume, 13 per cent smaller uteruses by volume and 23 per cent fewer ovarian follicles – the sacs that nurture immature eggs – compared with those who weren’t exposed. Higher doses were associated with a bigger effect, says Fischer, but no women took more than the recommended daily maximum of 4000 milligrams.

From autism to migraines, birth order may have wide-reaching effects

A study of more than 10 million siblings suggests that firstborns are more likely to be autistic and have allergies, while conditions like migraine and shingles tend to affect their younger sibling

The researchers also analysed data from another study on 1210 girls born in Copenhagen between 1997 and 2002, and found a link between fetal exposure to paracetamol and smaller ovaries during adolescence.

In animal studies, such effects led to reduced fertility and earlier reproductive ageing, but it isn’t clear whether this applies to people. “We cannot say anything about the reproductive consequences for these girls,” says Fischer. That will require long-term follow-up, which is hard to do.

The team also examined the boys who were born to the 685 women. “We do see a difference, on average, in the boys as well,” says Fischer. “[They] have a reduced testicular volume.”

Animal studies suggest this could affect fertility in adulthood, but again it is still unclear if this will be the case for the boys. “We can’t say anything about that because our cohort does not follow them that long,” she says.

A paper describing the findings in girls was published today. A separate paper describing the findings in boys has been accepted by the same journal, but not yet published, says Fischer.

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“It is still too early to sound the alarm, and to remove this tool from the therapeutic arsenal for treating pain and fever,” says at the National Institute of Health and Medical Research in France, who, in 2022, co-authored research showing that .

But this latest study, along with one from last year showing that paracetamol , suggest that the precautionary principle should be applied, especially during the first trimester, says Mazaud-Guittot.

“Raising awareness of alternative, non-pharmacological methods should help to encourage a reduction in the use of medication for the treatment of various mild pains,” she says.

“This paper would not change my practice or advice,” says at University College London. The team carried out a number of different statical analyses, he says, and the more of these you do, the greater the odds of getting a statistically significant association by chance.

“I do agree that we cannot exclude the possibility of chance findings,” says Fischer. “[But] adjusting for multiple testing could mean that we fail to detect a real effect.”

Childbirth for many primate species is even harder than for humans

For decades, we’ve thought that childbirth is uniquely challenging for humans, but it turns out that many other primates find the birth process just as difficult

Another issue is that people taking these medications could be sicker, including with one of the many infections that affect fetal development. They might also eat and behave differently, or vary genetically, says at the University of Pennsylvania. The team tried to take account of such confounding factors, but couldn’t completely rule them out.

“I would not jump to the conclusion that the statistical association observed is a causal association,” says Lee. He thinks there should be further studies into this, but establishing a causal link, if there is one, won’t be easy. A trial in which women were randomly assigned to take paracetamol or not would be the best way, but this would be unethical in pregnant women, says Fischer.

There have been claims that taking paracetamol during pregnancy increases the risk of autism, but the evidence suggests otherwise. “This in no way changes the conclusion that paracetamol is not linked to autism, as multiple studies featuring millions of pregnancies across Sweden, Denmark, Norway, Hong Kong, Taiwan and Japan have shown,” says Lee.

OpenAI claims one of its AI models has found a solution to the Navier-Stokes problem, one of the toughest and most enduring puzzles in mathematics, sitting on the list of Millennium Prize Problems, solutions for which come with a $1 million reward. The announcement came after an unusual flurry of activity around the problem, along with a dispute around how the work came about.

The Navier-Stokes equations describe how fluids move in space, such as air over an aircraft wing or water out of a tap. Though the equations were first written down around 200 years ago, they aren’t well understood. The question posed by the Clay Mathematics Institute for the Millennium Prize Problem is to determine if the equations always work or if there are situations where they stop making sense and start spouting nonsense, what mathematicians call “blow-ups”.

To settle the question, OpenAI first set 1000 AI agents on the Euler problem, which is a cousin of the Navier-Stokes problem and a step on the path to a full solution. It took the agents 50 hours to find blow-ups in this case. They then set 10,000 agents the task of extending the blow-ups to apply to the full Navier-Stokes problem, which took just 11 hours to finish.

OpenAI said during a press conference that if a customer wanted to run the same problem, it would cost around $15 million. OpenAI didn’t name the AI model used, but said it was “significantly more capable” than even its latest GPT-6 Astra model.

“This problem has remained unsolved for 200 years because the Navier-Stokes equations are just so enormously complex, and the pen-and-paper calculations you need to do in order to solve this problem are just mind-bogglingly intricate,” says Venkat Chandrasekaran at OpenAI, who was also on the press conference call.

at OpenAI says the news is the “spectacular combination of the arc we have seen over the last 12 months”.

The result is the latest in a string of shocking mathematical discoveries led by AI in recent months. In May, an OpenAI model cracked a decades-old conjecture by Paul ErdƑs, causing a stir in mathematical circles. Later, the Claude Fable 5 AI found a counterexample to the Jacobian conjecture, which had stood for nearly a century. Last week, an AI model formalised Fermat’s last theorem in just 11 days.

OpenAI’s latest groundbreaking mathematical discovery came just hours after  at New York University and  at AI company Anthropic announced that they had cracked three significant problems considered “stepping stones” to the Navier-Stokes problem.

Buckmaster and Alpöge also showed that blow-ups can appear in Euler equations; OpenAI has now shown that the same is true of Navier-Stokes.

Buckmaster and Alpöge said they received a “great deal of help from” large language models (LLMs), including LLMs from Anthropic and OpenAI. But when rumours suggested that OpenAI had gone one step further and solved the wider Navier-Stokes puzzle – something the company formally announced just hours later – Buckmaster released a statement suggesting that OpenAI acted unusually and opaquely when he approached the company for clarification.

Buckmaster wrote in a that, as a result of these rumours, he emailed a prominent mathematician at OpenAI to clarify matters. He says that in a subsequent meeting with OpenAI staff, he was given no hard details about how OpenAI achieved the result, but he took what little he was told as a “red flag”, as it appeared to describe the same technique and path that he and Levent had followed to achieve their interim findings. 

According to Buckmaster, OpenAI then admitted it hadn’t started its own AI search for a solution until after it had heard of his and Alpöge’s work, and didn’t respond to questions about whether its AI model had been trained or fine-tuned on that existing work – which was being stored in OpenAI’s Codex model, where the company would theoretically have access to it. The pair had used Codex as a customer, not a research partner, so expected that their work should remain secure and private.

Buckmaster makes it clear in his version of events that he is making no claims or accusations about how OpenAI arrived at its solution, saying only that he wished the focus could instead be on the mathematics rather than scandal and intrigue. “I have not seen OpenAI’s proof. I do not know what their model did, or how. I do not know whether our data was used. I am not accusing anyone of anything,” he wrote in the posted document.

In a press conference announcing its discovery, OpenAI categorically denied using Buckmaster and Alpöge’s proof or prompts in its work. It also said that its model’s proof of Euler is different to that put forward by Buckmaster and Alpöge. 

It also said that no humans accessed Codex to see work in progress within. Mark Chen at OpenAI, when asked if that also applied to any of the thousands of AI agents that had worked on the problem, said “that’s also our understanding”.

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Though the solution to this Navier-Stokes problem has been a long time coming, AI-generated proofs are often hard to understand and rarely bring the same level of new insight than those created by humans. “There’s been this very strange and unprecedented decoupling, this year alone, between getting answers and getting understanding,” says at University of California, Los Angeles. He says that AI is coming up with new results so quickly that there is not enough time for the “slow, deliberate discussion” needed to unpack them.

Something that will happen slowly is determining how the $1 million Millennium Prize money will be awarded. “The process of evaluation is deliberately unhurried, and we shall ensure that it is absolutely rigorous,” wrote , president of the Clay Mathematics Institute, to Âé¶čŽ«Ăœ in an email.

Growing seaweed has long been as a way to slow climate change. But this approach is mistaken, a new study argues, as the loss of seaweed emits far more carbon than what is being absorbed by attempts to grow it.

Seaweeds absorb an estimated 3.7 billion tonnes of carbon dioxide through photosynthesis every year, drawing it from seawater, which then draws more CO2 from the air above. They mostly grow near the coast, where they are eventually digested or decomposed, emitting carbon. But fragments of fronds, as well as from the seaweeds that dissolve in seawater, can sink into the deep sea, sequestering a of the CO2 as “” for thousands of years.

Scientists and start-ups have suggested that seaweed growth, especially kelp, could be expanded to take up more CO2, something the UN has said we will need to do on a massive scale to eventually reverse dangerous levels of global warming.

But there are concerns that cultivating huge amounts of seaweed could backfire and diminish growth of phytoplankton, another important carbon sink. And even the kelp forests we currently have, which are estimated to cover around 640,000 square kilometres worldwide – an area slightly larger than France – are dying off as ocean temperatures reach record highs.

Now, at the University of Western Australia and her colleagues have concluded that, with some 60 per cent of kelp forests in decline, these ecosystems could eventually begin emitting more CO2 than they absorb. Researchers, as well as governments and companies trying to offset their emissions, need to focus on preserving rather than growing seaweed, they suggest.

“Instead of asking how much carbon we can remove with seaweeds, we should be asking how much carbon we can stop from being released as these ecosystems are damaged by climate change,” says Filbee-Dexter.

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Some studies have the possibility of removing a billion tonnes of carbon per year with seaweed, but there are already signs that this may not be feasible. For instance, the US carbon removal start-up Running Tide, which raised $70 million to cultivate kelp on wooden buoys that would gradually sink into the deep sea, in the open ocean and shut down last year.

Other projects have tried to bring back lost kelp forests. An experiment in northern Norway of kelp by poisoning seaweed-eating sea urchins, which can multiply when overfishing and hunting remove their predators.

While kelp restoration like this is a win for biodiversity, it only draws down about 50,000 tonnes of CO2 per year. Meanwhile, global kelp loss is emitting an estimated 14 million tonnes of CO2 per year.

The study by Filbee-Dexter and her colleagues also notes that preserving kelp ecosystems is at least eight times cheaper per hectare than restoring them, yet only 2 per cent of kelp forests lie in protected areas.

Firms are also cultivating seaweed to make nori for sushi, animal feed and thickeners for products like ice cream and toothpaste. Fragments of seaweed still drift away and sink into the deep sea, and aquaculture companies like Kelp Blue have to eventually sequester and offset hundreds of millions of tonnes of CO2.

Seaweed farming now takes up 4000 square kilometres of ocean. But that’s only about a third of the kelp forest cover lost each year. And after factoring in emissions associated with farming operations – like boat fuel and plastic lines – nine out of 11 seaweed farms were found to emit more CO2 than they sequestered in a .

Microplastics could be hampering the ocean’s ability to capture carbon

A global survey of microplastics in oceans reveals that tiny particles of plastic are prevalent throughout the water column, which could harm marine ecosystems and affect carbon storage in the deep sea

“Seaweed restoration and farming is unlikely to be a major climate change solution,” Filbee-Dexter says. “But that doesn’t mean it isn’t worthwhile.”

Restoration can improve biodiversity, and farming can make low-carbon alternatives to fossil-fuel products like fertiliser, she notes.

at Queen’s University Belfast in the UK, however, says scientists don’t have a solid enough understanding of how much carbon seaweed sequesters to write it off yet. Macroalgae restoration, conservation and farming can all still be climate solutions, even if their impact has often been exaggerated in the past, she argues.

“Blue carbon is part of the puzzle,” she says. “It can make a contribution. The question is how that is determined and validated.”

People with chronic lung disease breathe better after two months of laughter therapy, results from a small trial show. The promising results may prompt further research into the low-cost treatment option.

In chronic obstructive pulmonary disease (COPD) – a leading cause of disability and death worldwide – air isn’t fully expelled when exhaling, meaning stale air remains trapped inside the lungs. The millions of people who are affected by the condition often feel breathless, even during simple daily activities.

Doctors treat COPD with medications like bronchodilators and corticosteroids, and may also recommend specialised breathing exercises. These include pursed-lip breathing, in which patients breathe in through the nose and out slowly through the lips, which creates a gentle build-up of pressure that helps release some of the air trapped in the lungs. But many people with COPD continue to become increasingly dependent on others for care over time, reducing their quality of life.

, formerly at Hacettepe University Faculty of Nursing in Ankara, Turkey, had seen research showing that laughter therapy shows promise in people with , and and thought it might help those with COPD as well – both physically and mentally.

To find out, she and her colleagues recruited 63 people who were already being treated for COPD at Ankara Bilkent City Hospital and divided them into three groups of 21. In their randomised controlled trial, all participants continued their medications, but those in one group additionally performed pursed-lip breathing exercises and those in another group received laughter therapy. Participants in the third, control, group did neither.

The laughter therapy is an established programme that differs from simple responses to humour. It includes playful exercises like mimicking a motorcycle starting or a lion roaring, rhythmic clapping with vocal sounds and relaxation with calm breathing and smiling. The participants were coached by laughter therapists in face-to-face sessions and then instructed to perform the techniques on their own for 30 minutes, three times per week.

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After eight weeks, participants in the laughter therapy and the pursed-lip breathing groups had less difficulty breathing and better overall health than those in the control group. Those benefits were still ongoing even a month after the trial ended, says Aldan. Even so, the therapies didn’t change how much daily assistance participants needed from caregivers. Aldan and her colleagues didn’t directly compare the effects of pursed-lip breathing and laughter therapy. They at the European Respiratory Society (ERS) Congress in Barcelona, Spain.

While more research could help clarify exactly how laughter therapy helps, Aldan suspects it might exercise the breathing muscles, promote deeper exhalation, improve lymphatic flow and trigger the release of endorphins, while also lowering levels of stress hormones.

“This structured approach may help facilitate gentle air expulsion and reduce air trapping without overwhelming the respiratory system,” she says. “Psychologically, it can also offer a safe, enjoyable way to reduce anxiety and support emotional wellbeing.”

Laughter therapy really could boost your emotional well-being

Structured interventions that encourage a good giggle, whether they are laughter yoga or clown visits, could have health benefits

Importantly, however, laughter therapy is distinct from intense or unguided laughter – like the response to a funny social media video – which can actually trigger adverse effects like acute airway collapse or exertion, says Aldan. “Laughter therapy is not merely ‘laughing’ – it is a structured protocol that naturally incorporates deep breathing exercises and rhythmic warm-ups to prepare the lungs and body for laughter.”

“This is a small but well-run study,” says at Vall d’Hebron University Hospital in Barcelona, Spain, who wasn’t involved in the research. “These results – showing that patients can breathe more easily and feel better in general – are promising. Laughter therapy is simple and low-cost, meaning it could be used by anyone, anywhere in the world. We look forward to further research in this area.”

The team hopes to expand its work with international collaborators.

Aedes aegypti mosquitoes and larvae – which can transmit infections like dengue, chikungunya and Zika virus – have been found breeding in the UK.

on 3 September that the species had been detected at residential properties in east London. This marks the fourth time it has been discovered in the UK in recent years, and the first time it has been found breeding.

The mosquitoes are usually found in more tropical climes. So, is this a result of climate change? How concerned should we be? Here’s what you need to know.

What do we know about A. aegypti?

A. aegypti mosquitoes are native to North Africa, but can be found in tropical and temperate regions around the world, including parts of Europe. Although the species has been seen in the UK before, this is the first time these mosquitoes have been found breeding in the country.

The species can transmit many different pathogens, including the dengue, yellow fever, chikungunya and Zika viruses. It commonly feeds at dusk and dawn, indoors and in shady areas.

Where were the mosquitoes found?

According to the UKHSA, the mosquitoes and larvae were found breeding in residential properties in east London. They were spotted and reported under the government’s scheme, which aims to detect the presence of invasive mosquitoes.

The UKHSA said the larvae have been destroyed and promised the area will be monitored closely to eradicate any further mosquitoes and larvae that might emerge.

What is the threat to public health?

The UKHSA insists the threat to public health remains very low. There is no evidence the A. aegypti mosquitoes found in London have transmitted any infections to people, and so far no more mosquitoes or larvae have been found in nearby public areas.

at the University of Oxford said in a statement to the Science Media Centre that the discovery of their presence should be seen as an “early warning rather than an immediate public-health threat”.

It is worth noting that the UK is home to many species of native mosquitoes, but these generally don’t carry serious infections, and are largely an annoyance rather than a public-health threat.

How did they get to the UK?

at the UKHSA said in a statement that the mosquitoes were likely to be “accidental importations”, having “hitchhiked” in vehicles, in suitcases or via imported plants.

Are these mosquitoes here to stay?

The UK has just had its hottest summer on record. London has seen some of the highest temperatures in the country, as heatwaves are usually amplified in cities due to the urban heat island effect.

That may mean the mosquitoes have been able to successfully breed over the summer months this year. But Medlock said the UK’s climate is still too cold overall to enable the mosquitoes to breed over the long term – for now.

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Is this a sign of climate change?

Mosquitoes are expanding their range north as the climate warms. Warmer weather also increases the rate at which viruses replicate in an insect’s body.

That means mosquito-borne viruses are rapidly becoming more common in Europe as the continent warms. In late August, cases of locally transmitted dengue, West Nile and chikungunya viruses across the country, including Paris.

And a published earlier this year found that the Asian tiger mosquito, another invasive mosquito species in Europe, can transmit chikungunya over several months of the year on the continent. The study authors said Europe’s rapid rate of warming was enabling virus transmission to become more widespread across the region.

Over time, the threat of mosquito-borne disease to the British public is also expected to rise. Last year, West Nile virus was detected in the UK for the first time in mosquitoes in Nottinghamshire. For now, authorities hope to keep invasive mosquitoes out of the country for as long as possible to prevent disease transmission.

Mosquito proboscis repurposed as a fine nozzle for 3D printing

When engineers struggled to make 3D printer nozzles narrow enough for their needs, they turned to nature and found the proboscis of a female mosquito had exactly the properties they needed

What should I do if I am stung by a mosquito?

For most people in the UK, a mosquito bite is an annoyance but nothing to worry about. It will usually produce a red, itchy swelling that will subside within a few days. If you develop a fever or become unwell, and have recently travelled to a location where dengue, chikungunya or Zika is circulating, you should seek medical attention.

How can I prevent mosquitoes breeding in my home?

Scientist say it is important to minimise the chance of mosquitoes breeding in the UK, to try to prevent invasive species gaining a foothold on UK shores. A. aegypti mosquitoes are well adapted to human environments and can breed in small quantities of standing water, so the most important action people can take is to eliminate, as far as possible, any standing water around the home. That could include emptying water trays under houseplants, clearing rainfall from containers, keeping lids on rain barrels, washing out pet bowls and flower vases regularly and keeping shower areas as clean and dry as possible between use.

If you spot a mosquito in the UK, you can report it to the scheme.