Researchers trace dust grain's journey through newborn solar system

A research team led by the University of Arizona has reconstructed in unprecedented detail the history of a dust grain that formed during the birth of the solar system more than 4.5 billion years ago. The findings provide insights into the fundamental processes underlying the formation of planetary systems, many of which are still shrouded in mystery.

For the study, the team developed a new type of framework, which combines quantum mechanics and thermodynamics, to simulate the conditions to which the grain was exposed during its formation, when the solar system was a swirling disk of gas and dust known as a protoplanetary disk or solar nebula. Comparing the predictions from the model to an extremely detailed analysis of the sample's chemical makeup and crystal structure, along with a model of how matter was transported in the solar nebula, revealed clues about the grain's journey and the environmental conditions that shaped it along the way.

The grain analyzed in the study is one of several inclusions, known as calcium-aluminum rich inclusions, or CAIs, discovered in a sample from the Allende meteorite, which fell over the Mexican state of Chihuahua in 1969. CAIs are of special interest because they are thought to be among the first solids that formed in the solar system more than 4.5 billion years ago.

Similar to how stamps in a passport tell a story about a traveler's journey and stops along the way, the samples' micro- and atomic-scale structures unlock a record of their formation histories, which were controlled by the collective environments to which they were exposed.

"As far as we know, our paper is the first to tell an origin story that offers clues about the likely processes that happened at the scale of astronomical distances with what we see in our sample at the scale of atomic distances," said Tom Zega, a professor in the University of Arizona's Lunar and Planetary Laboratory and the first author of the paper, published in The Planetary Science Journal.

Zega and his team analyzed the composition of the inclusions embedded in the meteorite using cutting-edge atomic-resolution scanning transmission electron microscopes -- one at UArizona's Kuiper Materials Imaging and Characterization Facility, and its sister microscope located at the Hitachi factory in Hitachinaka, Japan.

The inclusions were found to consist mainly of types of minerals known as spinel and perovskite, which also occur in rocks on Earth and are being studied as candidate materials for applications such as microelectronics and photovoltaics.

Similar kinds of solids occur in other types of meteorites known as carbonaceous chondrites, which are particularly interesting to planetary scientists as they are known to be leftovers from the formation of the solar system and contain organic molecules, including those that may have provided the raw materials for life.

Precisely analyzing the spatial arrangement of atoms allowed the team to study the makeup of the underlying crystal structures in great detail. To the team's surprise, some of the results were at odds with current theories on the physical processes thought to be active inside protoplanetary disks, prompting them to dig deeper.

"Our challenge is that we don't know what chemical pathways led to the origins of these inclusions," Zega said. "Nature is our lab beaker, and that experiment took place billions of years before we existed, in a completely alien environment."

Zega said the team set out to "reverse-engineer" the makeup of the extraterrestrial samples by designing new models that simulated complex chemical processes, which the samples would be subjected to inside a protoplanetary disk.

"Such models require an intimate convergence of expertise spanning the fields of planetary science, materials science, mineral science and microscopy, which was what we set out to do," added Krishna Muralidharan, a study co-author and an associate professor in the UArizona's Department of Materials Science and Engineering.

Based on the data the authors were able to tease from their samples, they concluded that the particle formed in a region of the protoplanetary disk not far from where Earth is now, then made a journey closer to the sun, where it was progressively hotter, only to later reverse course and wash up in cooler parts farther from the young sun. Eventually, it was incorporated into an asteroid, which later broke apart into pieces. Some of those pieces were captured by Earth's gravity and fell as meteorites.

The samples for this study were taken from the inside of a meteorite and are considered primitive -- in other words, unaffected by environmental influences. Such primitive material is believed to not have undergone any significant changes since it first formed more than 4.5 billion years ago, which is rare. Whether similar objects occur in asteroid Bennu, samples of which will be returned to Earth by the UArizona-led OSIRIS-REx mission in 2023, remains to be seen. Until then, scientists rely on samples that fall to Earth via meteorites.

"This material is our only record of what happened 4.567 billion years ago in the solar nebula," said Venkat Manga, a co-author of the paper and an assistant research professor in the UArizona Department of Materials Science and Engineering. "Being able to look at the microstructure of our sample at different scales, down to the length of individual atoms, is like opening a book."

The authors said that studies like this one could bring planetary scientists a step closer to "a grand model of planet formation" -- a detailed understanding of the material moving around the disk, what it is composed of, and how it gives rise to the sun and the planets.

Powerful radio telescopes like the Atacama Large Millimeter/submillimeter Array, or ALMA, in Chile now allow astronomers to see stellar systems as they evolve, Zega said.

"Perhaps at some point we can peer into evolving disks, and then we can really compare our data between disciplines and begin answering some of those really big questions," Zega said. "Are these dust particles forming where we think they did in our own solar system? Are they common to all stellar systems? Should we expect the pattern we see in our solar system -- rocky planets close to the central star and gas giants farther out -- in all systems?

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'Pack ice' tectonics reveal Venus' geological secrets

A new analysis of Venus' surface shows evidence of tectonic motion in the form of crustal blocks that have jostled against each other like broken chunks of pack ice. The movement of these blocks could indicate that Venus is still geologically active and give scientists insight into both exoplanet tectonics and the earliest tectonic activity on Earth.

"We've identified a previously unrecognized pattern of tectonic deformation on Venus, one that is driven by interior motion just like on Earth," says Paul Byrne, associate professor of planetary science at North Carolina State University and lead and co-corresponding author of the work. "Although different from the tectonics we currently see on Earth, it is still evidence of interior motion being expressed at the planet's surface."

The finding is important because Venus has long been assumed to have an immobile solid outer shell, or lithosphere, just like Mars or Earth's moon. In contrast, Earth's lithosphere is broken into tectonic plates, which slide against, apart from, and underneath each other on top of a hot, weaker mantle layer.

Byrne and an international group of researchers used radar images from NASA's Magellan mission to map the surface of Venus. In examining the extensive Venusian lowlands that make up most of the planet surface, they saw areas where large blocks of the lithosphere seem to have moved: pulling apart, pushing together, rotating and sliding past each other like broken pack ice over a frozen lake.

The team created a computer model of this deformation, and found that sluggish motion of the planet's interior can account for the style of tectonics seen at the surface.

"These observations tell us that interior motion is driving surface deformation on Venus, in a similar way to what happens on Earth," Byrne says. "Plate tectonics on Earth are driven by convection in the mantle. The mantle is hot or cold in different places, it moves, and some of that motion transfers to Earth's surface in the form of plate movement.

"A variation on that theme seems to be playing out on Venus as well. It's not plate tectonics like on Earth -- there aren't huge mountain ranges being created here, or giant subduction systems -- but it is evidence of deformation due to interior mantle flow, which hasn't been demonstrated on a global scale before."

The deformation associated with these crustal blocks could also indicate that Venus is still geologically active.

"We know that much of Venus has been volcanically resurfaced over time, so some parts of the planet might be really young, geologically speaking," Byrne says. "But several of the jostling blocks have formed in and deformed these young lava plains, which means that the lithosphere fragmented after those plains were laid down. This gives us reason to think that some of these blocks may have moved geologically very recently -- perhaps even up to today."

The researchers are optimistic that Venus' newly recognized "pack ice" pattern could offer clues to understanding tectonic deformation on planets outside of our solar system, as well as on a much younger Earth.

"The thickness of a planet's lithosphere depends mainly upon how hot it is, both in the interior and on the surface," Byrne says. "Heat flow from the young Earth's interior was up to three times greater than it is now, so its lithosphere may have been similar to what we see on Venus today: not thick enough to form plates that subduct, but thick enough to have fragmented into blocks that pushed, pulled, and jostled."

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Worrying insights into the chemicals in plastics

Plastic is practical, cheap and incredibly popular. Every year, more than 350 million tonnes are produced worldwide. These plastics contain a huge variety of chemicals that may be released during their lifecycles -- including substances that pose a significant risk to people and the environment. However, only a small proportion of the chemicals contained in plastic are publicly known or have been extensively studied.

A team of researchers led by Stefanie Hellweg, ETH Professor of Ecological Systems Design, has for a first time compiled a comprehensive database of plastic monomers, additives and processing aids for use in the production and processing of plastics on the world market, and systematically categorized them on the basis of usage patterns and hazard potential. The study, just published in the scientific journal Environmental Science & Technology, provides an enlightening but worrying insight into the world of chemicals that are intentionally added to plastics.

A high level of chemical diversity

The team identified around 10,500 chemicals in plastic. Many are used in packaging (2,489), textiles (2,429) and food-contact applications (2,109); some are for toys (522) and medical devices, including masks (247). Of the 10,500 substances identified, the researchers categorized 2,480 substances (24 percent) as substances of potential concern.

"This means that almost a quarter of all the chemicals used in plastic are either highly stable, accumulate in organisms or are toxic. These substances are often toxic to aquatic life, cause cancer or damage specific organs," explains Helene Wiesinger, doctoral student at the Chair of Ecological Systems Design and lead author of the study. About half are chemicals with high production volumes in the EU or the US.

"It is particularly striking that many of the questionable substances are barely regulated or are ambiguously described," continues Wiesinger.

In fact, 53 percent of all the substances of potential concern are not regulated in the US, the EU or Japan. More surprisingly, 901 hazardous substances are approved for use in food contact plastics in these regions. Finally, scientific studies are lacking for about 10 percent of the identified substances of potential concern.

Plastic monomers, additives and processing aids

Plastics are made of organic polymers built up from repeating monomer units. A wide variety of additives, such as antioxidants, plasticisers and flame retardants, give the polymer matrix the desired properties. Catalysts, solvents and other chemicals are also used as processing aids in production.

"Until now, research, industry and regulators have mainly concentrated on a limited number of dangerous chemicals known to be present in plastics," says Wiesinger. Today, plastic packaging is seen as a main source of organic contamination in food, while phthalate plasticisers and brominated flame retardants are detectable in house dust and indoor air. Earlier studies have already indicated that significantly more plastic chemicals used worldwide are potentially hazardous.

Nevertheless, the results of the inventory came as an unpleasant surprise to the researchers. "The unexpectedly high number of substances of potential concern is worrying," says Zhanyun Wang, senior scientist in Hellweg's group. Exposure to such substances can have a negative impact on the health of consumers and workers and on polluted ecosystems. Problematic chemicals can also affect recycling processes and the safety and quality of recycled plastics.

Wang stresses that even more chemicals in plastics could be problematic. "Recorded hazard data are often limited and scattered. For 4,100 or 39 percent of all the substances we identified, we were not able to categorize them due to a lack of hazard classifications" he says.

A lack of data and transparency

The two researchers identified the lack of transparency in chemicals in plastics and dispersed data silos as a main problem. In over two and a half years of detective work, they combed through more than 190 publicly accessible data sources from research, industry and authorities and identified 60 sources with sufficient information about intentionally added substances in plastics. "We found multiple critical knowledge and data gaps, in particular for the substances and their actual uses. This ultimately hinders consumers' choice of safe plastic products," they say.

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New position statement declares that sleep is essential to health

A new position statement from the American Academy of Sleep Medicine emphasizes that sleep is a biological necessity, and insufficient sleep and untreated sleep disorders are detrimental for health, well-being, and public safety.

Published online in the Journal of Clinical Sleep Medicine, the statement notes that sleep is vital for health and well-being in children, adolescents, and adults. While awareness of the value of sleep has risen in the last decade, there is a significant need for greater emphasis on sleep health in education, clinical practice, inpatient and long-term care, public health promotion, and the workplace.

"Healthy sleep is as important as proper nutrition and regular exercise for our health and well-being, and sleep is critical for performance and safety," said AASM President Dr. Kannan Ramar. "It is the position of the AASM that sleep is essential to health, and we are urging educators, health care professionals, government agencies, and employers to prioritize the promotion of healthy sleep."

The statement was written by the members of the 2020 -- 2021 AASM board of directors, comprising 11 sleep medicine physicians and a clinical psychologist. In recognition of sleep's significant and multi-faceted connections to health and chronic disease, the authors outlined the following positions:

    - Sleep education should have a prominent place in K-12 and college health education, medical school    and graduate medical education, and educational programs for other health professionals.

    - Clinicians should routinely inquire about sleep habits and symptoms of sleep and circadian rhythm sleep-wake disorders during patient encounters, and hospitals and long-term care facilities should optimize sleep conditions.

    - Healthy sleep should be targeted by public health and workplace interventions to improve health-related outcomes, and behaviors that help people attain healthy sleep should be actively promoted.

    - More sleep and circadian research is needed to further elucidate the importance of sleep for public health and the contributions of insufficient sleep to health disparities.

"Education about sleep and sleep disorders is lacking in medical school curricula, graduate medical education, and education programs for other health professionals," said Ramar. "Better sleep health education will enable our health care workforce to provide more patient-centered care for people who have common sleep disorders such as obstructive sleep apnea and insomnia."

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New geochemical study confirms cause of end-Permian mass extinction event

The most severe mass extinction event in the past 540 million years eliminated more than 90 percent of Earth's marine species and 75 percent of terrestrial species. Although scientists had previously hypothesized that the end-Permian mass extinction, which took place 251 million years ago, was triggered by voluminous volcanic eruptions in a region of what is now Siberia, they were not able to explain the mechanism by which the eruptions resulted in the extinction of so many different species, both in the oceans and on land.

Associate professor Laura Wasylenki of Northern Arizona University's School of Earth and Sustainability and Department of Chemistry and Biochemistry is co-author on a new paper in Nature Communications entitled, "Nickel isotopes link Siberian Traps aerosol particles to the end-Permian mass extinction," in collaboration with Chinese, Canadian and Swiss scientists. The paper presents the results of nickel isotope analyses performed in Wasylenki's lab on Late Permian sedimentary rocks collected in Arctic Canada. The samples have the lightest nickel isotope ratios ever measured in sedimentary rocks, and the only plausible explanation is that the nickel was sourced from the volcanic terrain, very likely carried by aerosol particles and deposited in the ocean, where it dramatically changed the chemistry of seawater and severely disrupted the marine ecosystem.

"The study results provide strong evidence that nickel-rich particles were aerosolized and dispersed widely, both through the atmosphere and into the ocean," Wasylenki said. "Nickel is an essential trace metal for many organisms, but an increase in nickel abundance would have driven an unusual surge in productivity of methanogens, microorganisms that produce methane gas. Increased methane would have been tremendously harmful to all oxygen-dependent life."

"Our data provide a direct link between global dispersion of Ni-rich aerosols, ocean chemistry changes and the mass extinction event," Wasylenki said. "The data also demonstrate that environmental degradation likely began well before the extinction event -- perhaps starting as early as 300,000 years before then. Prior to this study, the connection between Siberian Traps flood basalt volcanism, marine anoxia and mass extinction was rather vague, but now we have evidence of a specific kill mechanism. This finding demonstrates the power of nickel isotope analyses, which are relatively new, to solve long-standing problems in the geosciences."

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Ancient bones provide clues about Kangaroo Island's past and future

A Curtin University-led study of ancient bones on South Australia's Kangaroo Island has provided new information about the Island's past fauna and an insight into how species may live there in the future.

Published in Quaternary Science Reviews, the researchers analysed around 2,000 bone fragments with the aim of eventually being able to establish a more complete picture of past biodiversity on the Island.

Lead researcher Dr Frederik Seersholm from Curtin's School of Molecular and Life Sciences said DNA studies on such a large scale have never been done on the Island before.

"We identified 33 species, 10 of which are extinct on the island today. We also found DNA traces from both the Eastern and the Western grey kangaroos- which is interesting given it was previously thought that only the Western used to roam the Island," Dr Seersholm said.

"Our research also discovered an extinct population of spotted-tailed quoll, different from both the modern mainland and Tasmanian populations, indicating that it once lived on Kangaroo Island and perhaps other parts of South Australia too.

"While Kangaroo Island is a renowned biodiversity hotspot, and natural haven for several threatened and endemic species, it has been continuously losing species richness since European arrival on the Island 200 years ago.

"From excavations of these ancient fossil bones, we now know more about the species that used to roam the Island before this human-caused decimation."

Dr Seersholm said this research was particularly important in the wake of the major bushfires of 2019/2020 which had a devastating impact on Kangaroo Island's pristine ecosystem.

"We hope our work in accurately identifying species can aid conservation and restoration efforts and help to restore the biodiversity on Kangaroo Island," Dr Seersholm said.

"While more research is needed in this area, our study has confirmed that Kangaroo Island could be a potential haven for the reintroduction of some species.

"If a quoll population should be introduced to the island, it is essential to get a detailed picture of the extinct quoll population. The research has also added the eastern grey kangaroo to the list of potential reintroduction candidates.

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mRNA vaccine yields full protection against malaria in mice

Scientists from the Walter Reed Army Institute of Research and Naval Medical Research Center partnered with researchers at the University of Pennsylvania and Acuitas Therapeutics to develop a novel vaccine based on mRNA technology that protects against malaria in animal models, publishing their findings in npj Vaccines.

In 2019, there were an estimated 229 million cases of malaria and 409,000 deaths globally, creating an extraordinary cost in terms of human morbidity, mortality, economic burden, and regional social stability. Worldwide, Plasmodium falciparum is the parasite species which causes the vast majority of deaths. Those at highest risk of severe disease include pregnant women, children and malaria naïve travelers. Malaria countermeasures development has historically been a priority research area for the Department of Defense as the disease remains a top threat to U.S. military forces deployed to endemic regions.

A safe, effective malaria vaccine has long been an elusive target for scientists. The most advanced malaria vaccine is RTS,S, a first-generation product developed in partnership with WRAIR. RTS,S is based on the circumsporozoite protein of P. falciparum, the most dangerous and widespread species of malaria parasite. While RTS,S is an impactful countermeasure in the fight against malaria, field studies have revealed limited sterile efficacy and duration of protection. The limitations associated with RTS,S and other first-generation malaria vaccines have led scientists to evaluate new platforms and second-generation approaches for malaria vaccines.

"Recent successes with vaccines against COVID-19 highlight the advantages of mRNA-based platforms -- notably highly targeted design, flexible and rapid manufacturing and ability to promote strong immune responses in a manner not yet explored," said Dr. Evelina Angov, a researcher at WRAIR's Malaria Biologics Branch and senior author on the paper. "Our goal is to translate those advances to a safe, effective vaccine against malaria."

Like RTS,S, the vaccine relies on P. falciparum's circumsporozoite protein to elicit an immune response. However, rather than administering a version of the protein directly, this approach uses mRNA -- accompanied by a lipid nanoparticle which protects from premature degradation and helps stimulate the immune system -- to prompt cells to code for circumsporozoite protein themselves. Those proteins then trigger a protective response against malaria but cannot actually cause infection.

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There's more to genes than DNA: How Mum and Dad add something extra, just for you

Biologists at the Universities of Bath and Vienna have discovered 71 new 'imprinted' genes in the mouse genome, a finding that takes them a step closer to unravelling some of the mysteries of epigenetics -- an area of science that describes how genes are switched on (and off) in different cells, at different stages in development and adulthood.

To understand the importance of imprinted genes to inheritance, we need to step back and ask how inheritance works in general. Most of the thirty trillion cells in a person's body contain genes that come from both their mother and father, with each parent contributing one version of each gene. The unique combination of genes goes part of the way to making an individual unique. Usually, each gene in a pair is equally active or inactive in a given cell. This is not the case for imprinted genes. These genes -- which make up less than one percent of the total of 20,000+ genes -- tend to be more active (sometimes much more active) in one parental version than the other.

Until now, researchers were aware of around 130 well-documented imprinted genes in the mouse genome -- the new additions take this number to over 200.

Professor Tony Perry, who led the research from the Department of Biology & Biochemistry at Bath in the UK, said: "Imprinting affects an important family of genes, with different implications for health and disease, so the seventy-plus new ones add an important piece of the jigsaw."

THE IMPORTANCE OF HISTONES

Close examination of the newly identified genes has allowed Professor Perry and his colleagues to make a second important discovery: the switching on and off of imprinted genes is not always related to DNA methylation, where methyl groups are added to genomic DNA- a process that is known to repress gene activity, switching them off). DNA methylation was the first known type of imprint, and was discovered around thirty years ago. From the results of the new work, it seems that a greater contribution to imprinting is made by histones -- structures that are wrapped up with genomic DNA in chromosomes.

Although scientists have known for some time that histones act as 'dimmer' switches for genes, fading them off (or back on), until now it was thought that DNA methylation provided the major switch for imprinted gene activity. The findings from the new study cast doubt on this assumption: many of the newly identified genes were found to be associated with changes to the histone 3 lysine 27 (H3K27me3), and only a minority with DNA methylation.

WHY IMPRINTING MATTERS

Scientists have yet to work out how one parental version of a given gene can be switched (or faded) on or off and maintained that way while the other is in the opposite state. It is known that much of the on/off switching occurs during the formation of gametes (sperm and egg), but the precise mechanisms remain unclear. This new study points to the intriguing possibility that some imprinted genes may not be marked in gametes, but become active later in development, or even in adulthood.

Although it only involves a small proportion of genes, imprinting is important in later life. If it goes wrong, and the imprinted gene copy from one parent is switched on when it should be off (or vice versa), disease or death occur. Faulty imprinted genes are associated with many diseases, including neurological and metabolic disorders, and cancer.

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Climate warming can influence fungal communities on oak leaves across the growing season

Climate warming plays a larger role than plant genes in influencing the number and identity of fungal species on oak leaves, especially in autumn. Recently published in the journal New Phytologist, this research by ecologists sheds light on how warming and tree genes affect the dynamics of fungal communities across the season.

"One of our major findings was that elevated temperature decreased the number of fungal species and changed their community composition, especially in the late season" says Maria Faticov, a researcher at the Department of Ecology, Environment and Plant Sciences (DEEP) at Stockholm University.

Plants host thousands of microscopic organisms and leaves are no exception. Leaves harbour a large diversity of microorganisms including fungi, bacteria and, less frequently, archaea. Fungi are among the most diverse groups of microorganisms living on leaves. Some of these microscopic fungi cause disease, others can promote plant growth and defend leaves against biotic and abiotic stresses, and still others play an important role in leaf senescence and decomposition.

Climate is one of the main factors influencing fungal development, either directly or indirectly, by triggering plant defences.

"From earlier studies, we know that the number of fungal species and their abundance change as leaves age and the season progresses from spring to autumn. What we do not know is what role climate warming and plant genetic variation play in shaping fungal communities across the growing season" says Ayco Tack, associate professor at the Department of Ecology, Environment and Plant Sciences, Stockholm University.

To answer this question, researchers took on a challenging project -- they built 6 identical cages in a field to the north of Stockholm, each cage the size of a small living room. Scientists put 132 young oak trees into the cages that represented 5 different genotypes. Half of the cages were heated from May to October using ceramic heaters. The remaining ones were left as control and did not have heaters in them. The temperature in the heated cages was increased by ca 2°C to mimic the global temperature increase predicted by scientists to occur by the end of the century. Researchers collected leaves in the early, middle and late growing season and used DNA sequencing to find out which fungi had colonised the leaves. This way they could compare the changes in fungal community structure between the control and warming treatment and also among oak genotypes.

"We observed that fungal community composition drastically changed from spring to autumn, with yeasts increasing in relative abundance and fungal pathogens decreasing. Interestingly, while experimental warming had a major impact on the fungal community, oak genotype explained only a minor part of the variation in the number of fungal species and their composition" says Maria Faticov.

These findings suggest that warming is one of the most important environmental factors shaping fungal community development during the growing season and emphasizes how profound the effects of ongoing climate change may be to plant health and ecosystem functioning.

Researchers did not link the observed change in fungal community structure under warming with plant health and ecosystem functioning. More detailed long-term experiments are needed to predict how changes in the fungal community under climate warming will influence the plants they live on and their surrounding environment.

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One in 6 families in new study spent more than $5,000 to have a baby

The price tag for giving birth in America may bring some families sticker shock -- even for those with private insurance.

And when delivering moms require caesarians or their newborns need neonatal care, some families may spend as much as $10,000 out-of-pocket, according to a new Michigan Medicine-led study.

"Childbirth is the most common reason for hospitalization in the U.S.," said lead author Kao-Ping Chua, M.D., Ph.D.,a pediatrician and researcher at University of Michigan Health C.S. Mott Children's Hospital and the Susan B. Meister Child Health Evaluation and Research Center.

"Our findings show that some privately insured families are shouldering an astoundingly high financial burden for childbirth-related hospitalizations."

During 2016-2019, privately insured families paid an average of $3,000 out-of-pocket for maternal and newborn hospitalizations, according to the research in Pediatrics. But for one in 6 families, out-of-pocket spending exceeded $5,000. And when neonatal intensive care was required, the price climbed to over $10,000 for about 1 in 11 families.

"Many privately insured families believe that if they have health insurance, they're protected from the costs of childbirth hospitalizations. Unfortunately, this is simply not true for many families, particularly if their baby needs NICU care," Chua said.

"Having a healthy baby is expensive enough given the costs of diapers, childcare, and baby equipment. Adding a $10,000 hospital bill on top of this can devastate some families."

Researchers analyzed national data of 12 million privately insured enrollees across all states in the country. They identified 398,410 maternal deliveries that were linked to at least one newborn hospitalization covered by the same family plan. Overall, average out-of-pocket spending for the delivery and newborn hospitalizations was $3,068.

When cesarean birth occurred, the average bill was $3,389. When NICU care was needed, the average bill was $4,969. This bill exceeded $10,000 for 9% of instances when NICU care was needed.

About 30% of the time, deliveries and newborn hospitalizations were covered by high-deductible health plans, such as a health reimbursement arrangement or health savings account. Out-of-pocket costs were primarily driven by deductibles and co-insurance.

Chua said he was inspired to pursue the study because of his own personal experience that involved a $5,000 out-of-pocket bill after the birth of his second daughter.

"This is an issue that impacts millions of Americans at some stage in their lives," he said.

"Before delivery, clinicians can help privately insured families understand their childbirth benefits. If large bills are expected, clinicians should advise families to save money, assuming they have the means to do so. After delivery, clinicians should screen families for financial hardship, particularly those experiencing resource-intensive hospitalizations, such as NICU care, and connect them with local resources to address food, housing, and financial insecurity."

While substantial cost-sharing may be justified for low-value care, childbirth is a necessary, high value service, says senior author Michelle Moniz, M.D., M.Sc.,an obstetrician gynecologist at University of Michigan Health Von Voigtlander Women's Hospital. Moniz says policies should aim to alleviate the financial burden of childbirth on families.

Ideally, insurers would waive most or all cost-sharing for these hospitalizations, consistent with the approach taken by Medicaid programs and many peer, high-resource countries, she says.

The new study adds to Moniz' previous study examining the out-of-pocket costs of pregnancy, delivery, and postpartum care for mothers. .

"Maternal and childbirth hospitalizations are essential to families' health and wellbeing, with some babies needing longer stays because of complex or unexpected medical conditions," Moniz said.

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