Why Don’t We Have Artificial Wombs for Premature Infants?
Ectogenesis, the development of a baby outside of the mother's body, is a concept that dates back to 1923. That year, British biochemist-geneticist J.B.S. Haldane gave a lecture to the "Heretics Society" of the University of Cambridge in which he predicted the invention of an artificial womb by 1960, leading to 70 percent of newborns being born that way by the 2070s. In reality, that's about when an artificial womb could be clinically operational, but trends in science and medicine suggest that such technology would come in increments, each fraught with ethical and social challenges.
An extra-uterine support device could be ready for clinical trials in humans in the next two to four years, with hopes that it could improve survival of very premature infants.
Currently, one major step is in the works, a system called an extra-uterine support device (EUSD) –or sometimes Ex-Vivo uterine Environment (EVE)– which researchers at the Children's Hospital of Philadelphia have been using to support fetal lambs outside the mother. It also has been called an artificial placenta, because it supplies nutrient- and oxygen-rich blood to the developing lambs via the umbilical vein and receives blood full of waste products through the umbilical arteries. It does not do everything that a natural placenta does, yet it does do some things that a placenta doesn't do. It breathes for the fetus like the mother's lungs, and encloses the fetus in sterile fluid, just like the amniotic sac. It represents a solution to one set of technical challenges in the path to an artificial womb, namely how to keep oxygen flowing into a fetus and carbon dioxide flowing out when the fetal lungs are not ready to function.
Capable of supporting fetal lambs physiologically equivalent to a human fetus at 23 weeks' gestation or earlier, the EUSD could be ready for clinical trials in humans in the next two to four years, with hopes that it could improve survival of very premature infants. Existing medical technology can keep human infants alive when born in this 23-week range, or even slightly less —the record is just below 22 weeks. But survival is low, because most of the treatment is directed at the lungs, the last major body system to mature to a functional status. This leads to complications not only in babies born before 24 weeks' gestation, but also in a fairly large number of births up to 28 weeks' gestation.
So, the EUSD is basically an advanced neonatal life support machine that beckons to square off the survival curve for infants born up to the 28th week. That is no doubt a good thing, but given the political prominence of reproductive issues, might any societal obstacles be looming?
"While some may argue that the EUSD system will shift the definition of viability to a point prior to the maturation of the fetus' lungs, ethical and legal frameworks must still recognize the mother's privacy rights as paramount."
Health care attorney and clinical ethicist David N. Hoffman points out that even though the EUSD may shift the concept of fetal viability away from the maturity of developing lungs, it would not change the current relationship of the fetus to the mother during pregnancy.
"Our social and legal frameworks, including Roe v. Wade, invite the view of the embryo-fetus as resembling a parasite. Not in a negative sense, but functionally, since it obtains its life support from the mother, while she does not need the fetus for her own physical health," notes Hoffman, who holds faculty appointments at Columbia University, and at the Benjamin N. Cardozo School of Law and the Albert Einstein College of Medicine, of Yeshiva University. "In contrast, our ethical conception of the relationship is grounded in the nurturing responsibility of parenthood. We prioritize the welfare of both mother and fetus ethically, but we lean toward the side of the mother's legal rights, regarding her health throughout pregnancy, and her right to control her womb for most of pregnancy. While some may argue that the EUSD system will shift the definition of viability to a point prior to the maturation of the fetus' lungs, ethical and legal frameworks must still recognize the mother's privacy rights as paramount, on the basis of traditional notions of personhood and parenthood."
Outside of legal frameworks, religion, of course, is a major factor in how society reacts to new reproductive technologies, and an artificial womb would trigger a spectrum of responses.
"Significant numbers of conservative Christians may oppose an artificial womb in fear that it might harm the central role of marriage in Christianity."
Speaking from the perspective of Lutheran scholarship, Dr. Daniel Deen, Assistant Professor of Philosophy at Concordia University in Irvine, Calif., does not foresee any objections to the EUSD, either theologically, or generally from Lutherans (who tend to be conservative on reproductive issues), since the EUSD is basically an improvement on current management of prematurity. But things would change with the advent of a full-blown artificial womb.
"Significant numbers of conservative Christians may oppose an artificial womb in fear that it might harm the central role of marriage in Christianity," says Deen, who specializes in the philosophy of science. "They may see the artificial womb as a catalyst for strengthening the mechanistic view of reproduction that dominates the thinking of secular society, and of other religious groups, including more liberal Christians."
Judaism, however, appears to be more receptive, even during the research phases.
"Even if researchers strive for a next-generation EUSD aimed at supporting a fetus several weeks earlier than possible with the current system, it still keeps the fetus inside the mother well beyond the 40-day threshold, so there likely are no concerns in terms of Jewish law," says Kalman Laufer, a rabbinical student and executive director of the Medical Ethics Society at Yeshiva University. Referring to a concept from the Babylonian Talmud that an embryo is "like water" until 40 days into pregnancy, at which time it receives a kind of almost-human status warranting protection, Laufer cautions that he's speaking about artificial wombs developed for the sake of rescuing very premature infants. At the same time though, he expects that artificial womb research will eventually trigger a series of complex, legalistic opinions from Jewish scholars, as biotechnology moves further toward supporting fetal growth entirely outside a woman's body.
"Since [the EUSD] gives some justification to end abortion, by transferring fetuses from mother to machine, conservatives will probably rally around it."
While the technology treads into uncomfortable territory for social conservatives at first glance, it's possible that the prospect of taking the abortion debate in a whole new direction could engender support for the artificial womb. "Since [the EUSD] gives some justification to end abortion, by transferring fetuses from mother to machine, conservatives will probably rally around it," says Zoltan Istvan, a transhumanist politician and journalist who ran for U.S. president in 2016. To some extent, Deen agrees with Istvan, provided we get to a point when the artificial womb is already a reality.
"The world has a way of moving forward despite the fear of its inhabitants," Deen notes. "If the technology gets developed, I could not see any Christians, liberal or conservative, arguing that people seeking abortion ought not opt for a 'transfer' versus an abortive procedure."
So then how realistic is a full-blown artificial womb? The researchers at the Children's Hospital of Philadelphia have noted various technical difficulties that would come up in any attempt to connect a very young fetus to the EUSD and maintain life. One issue is the small umbilical cord blood vessels that must be connected to the EUSD as fetuses of decreasing gestational age are moved outside the mother. Current procedures might be barely adequate for integrating a human fetus into the device in the 18 -21 week range, but going to lower gestational ages would require new technology and different strategies. It also would require numerous other factors to cover for fetal body systems that mature ahead of the lungs and that the current EUSD system is not designed to replace. However, biotechnology and tissue engineering strategies on the horizon could be added to later EUSDs. To address the blood vessel size issue, artificial womb research could benefit by drawing on experts in microfluidics, the field concerned with manipulation of tiny amounts of fluid through very small spaces, and which is ushering in biotech innovations like the "lab on a chip".
"The artificial womb might put fathers on equal footing with mothers, since any embryo could potentially achieve personhood without ever seeing the inside of a woman's uterus."
If the technical challenges to an artificial womb are indeed overcome, reproductive policy debates could be turned on their side.
"Evolution of the EUSD into a full-blown artificial external uterus has ramifications for any reproductive rights issues where policy currently assumes that a mother is needed for a fertilized egg to become a person," says Hoffman, the ethicist and legal scholar. "If we consider debates over whether to keep cryopreserved human embryos in storage, destroy them, or utilize them for embryonic stem cell research or therapies, the artificial womb might put fathers on equal footing with mothers, since any embryo could potentially achieve personhood without ever seeing the inside of a woman's uterus."
Such a scenario, of course, depends on today's developments not being curtailed or sidetracked by societal objections before full-blown ectogenesis is feasible. But if this does ever become a reality, the history of other biotechnologies suggests that some segment of society will embrace the new innovation and never look back.
Two-and-a-half year-old Huckleberry, a blue merle Australian shepherd, pulls hard at her leash; her yelps can be heard by skiers and boarders high above on the chairlift that carries them over the ski patrol hut to the top of the mountain. Huckleberry is an avalanche rescue dog — or avy dog, for short. She lives and works with her owner and handler, a ski patroller at Breckenridge Ski Resort in Colorado. As she watches the trainer play a game of hide-and-seek with six-month-old Lume, a golden retriever and avy dog-in-training, Huckleberry continues to strain on her leash; she loves the game. Hide-and-seek is one of the key training methods for teaching avy dogs the rescue skills they need to find someone caught in an avalanche — skier, snowmobiler, hiker, climber.
Lume’s owner waves a T-shirt in front of the puppy. While another patroller holds him back, Lume’s owner runs away and hides. About a minute later — after a lot of barking — Lume is released and commanded to “search.” He springs free, running around the hut to find his owner who reacts with a great amount of excitement and fanfare. Lume’s scent training will continue for the rest of the ski season (Breckenridge plans operating through May or as long as weather permits) and through the off-season. “We make this game progressively harder by not allowing the dog watch the victim run away,” explains Dave Leffler, Breckenridge's ski patroller and head of the avy dog program, who has owned, trained and raised many of them. Eventually, the trainers “dig an open hole in the snow to duck out of sight and gradually turn the hole into a cave where the dog has to dig to get the victim,” explains Leffler.
By the time he is three, Lume, like Huckleberry, will be a fully trained avy pup and will join seven other avy dogs on Breckenridge ski patrol team. Some of the team members, both human and canine, are also certified to work with Colorado Rapid Avalanche Deployment, a coordinated response team that works with the Summit County Sheriff’s office for avalanche emergencies outside of the ski slopes’ boundaries.
There have been 19 avalanche deaths in the U.S. this season, according to avalanche.org, which tracks slides; eight in Colorado. During the entirety of last season there were 17. Avalanche season runs from November through June, but avalanches can occur year-round.
High tech and high stakes
Complementing avy dogs’ ability to smell people buried in a slide, avalanche detection, rescue and recovery is becoming increasingly high tech. There are transceivers, signal locators, ground scanners and drones, which are considered “games changers” by many in avalanche rescue and recovery
For a person buried in an avalanche, the chance of survival plummets after 20 minutes, so every moment counts.
A drone can provide thermal imaging of objects caught in a slide; what looks like a rock from far away might be a human with a heat signature. Transceivers, also known as beacons, send a signal from an avalanche victim to a companion. Signal locators, like RECCO reflectors which are often sewn directly into gear, can echo back a radar signal sent by a detector; most ski resorts have RECCO detector units.
Research suggests that Ground Penetrating Radar (GPR), an electromagnetic tool used by geophysicists to pull images from inside the ground, could be used to locate an avalanche victim. A new study from the Department of Energy’s Sandia National Laboratories suggests that a computer program developed to pinpoint the source of a chemical or biological terrorist attack could also be used to find someone submerged in an avalanche. The search algorithm allows for small robots (described as cockroach-sized) to “swarm” a search area. Researchers say that this distributed optimization algorithm can help find avalanche victims four times faster than current search mechanisms. For a person buried in an avalanche, the chance of survival plummets after 20 minutes, so every moment counts.
An avy dog in training is picking up scent
Sarah McLear
While rescue gear has been evolving, predicting when a slab will fall remains an emerging science — kind of where weather forecasting science was in the 1980s. Avalanche forecasting still relies on documenting avalanches by going out and looking,” says Ethan Greene, director of the Colorado Avalanche Information Center (CAIC). “So if there's a big snowstorm, and as you might remember, most avalanches happened during snowstorms, we could have 10,000 avalanches that release and we document 50,” says Greene. “Avalanche forecasting is essentially pattern recognition,” he adds--and understanding the layering structure of snow.
However, determining where the hazards lie can be tricky. While a dense layer of snow over a softer, weaker layer may be a recipe for an avalanche, there’s so much variability in snowpack that no one formula can predict the trigger. Further, observing and measuring snow at a single point may not be representative of all nearby slopes. Finally, there’s not enough historical data to help avalanche scientists create better prediction models.
That, however, may be changing.
Last year, an international group of researchers created computer simulations of snow cover using 16 years of meteorological data to forecast avalanche hazards, publishing their research in Cold Regions Science and Technology. They believe their models, which categorize different kinds of avalanches, can support forecasting and determine whether the avalanche is natural (caused by temperature changes, wind, additional snowfall) or artificial (triggered by a human or animal).
With smell receptors ranging from 800 million for an average dog, to 4 billion for scent hounds, canines remain key to finding people caught in slides.
With data from two sites in British Columbia and one in Switzerland, researchers built computer simulations of five different avalanche types. “In terms of real time avalanche forecasting, this has potential to fill in a lot of data gaps, where we don't have field observations of what the snow looks like,” says Simon Horton, a postdoctoral fellow with the Simon Fraser University Centre for Natural Hazards Research and a forecaster with Avalanche Canada, who participated in the study. While complex models that simulate snowpack layers have been around for a few decades, they weren’t easy to apply until recently. “It's been difficult to find out how to apply that to actual decision-making and improving safety,” says Horton. If you can derive avalanche problem types from simulated snowpack properties, he says, you’ll learn “a lot about how you want to manage that risk.”
The five categories include “new snow,” which is unstable and slides down the slope, “wet snow,” when rain or heat makes it liquidly, as well as “wind-drifted snow,” “persistent weak layers” and “old snow.” “That's when there's some type of deeply buried weak layer in the snow that releases without any real change in the weather,” Horton explains. “These ones tend to cause the most accidents.” One step by a person on that structurally weak layer of snow will cause a slide. Horton is hopeful that computer simulations of avalanche types can be used by scientists in different snow climates to help predict hazard levels.
Greene is doubtful. “If you have six slopes that are lined up next to each other, and you're going to try to predict which one avalanches and the exact dimensions and what time, that's going to be really hard to do. And I think it's going to be a long time before we're able to do that,” says Greene.
What both researchers do agree on, though, is that what avalanche prediction really needs is better imagery through satellite detection. “Just being able to count the number of avalanches that are out there will have a huge impact on what we do,” Greene says. “[Satellites] will change what we do, dramatically.” In a 2022 paper, scientists at the University of Aberdeen in England used satellites to study two deadly Himalayan avalanches. The imaging helped them determine that sediment from a 2016 ice avalanche plus subsequent snow avalanches contributed to the 2021 avalanche that caused a flash flood, killing over 200 people. The researchers say that understanding the avalanches characteristics through satellite imagery can inform them how one such event increases the magnitude of another in the same area.
Avy dogs trainers hide in dug-out holes in the snow, teaching the dogs to find buried victims
Sarah McLear
Lifesaving combo: human tech and Mother Nature’s gear
Even as avalanche forecasting evolves, dogs with their built-in rescue mechanisms will remain invaluable. With smell receptors ranging from 800 million for an average dog, to 4 billion for scent hounds, canines remain key to finding people caught in slides. (Humans in comparison, have a meager 12 million.) A new study published in the Journal of Neuroscience revealed that in dogs smell and vision are connected in the brain, which has not been found in other animals. “They can detect the smell of their owner's fingerprints on a glass slide six weeks after they touched it,” says Nicholas Dodman, professor emeritus at Cummings School of Veterinary Medicine at Tufts University. “And they can track from a boat where a box filled with meat was buried in the water, 100 feet below,” says Dodman, who is also co-founder and president of the Center for Canine Behavior Studies.
Another recent study from Queens College in Belfast, United Kingdom, further confirms that dogs can smell when humans are stressed. They can also detect the smell of a person’s breath and the smell of the skin cells of a deceased person.
The emerging avalanche-predicting human-made tech and the incredible nature-made tech of dogs’ olfactory talents is the lifesaving “equipment” that Leffler believes in. Even when human-made technology develops further, it will be most efficient when used together with the millions of dogs’ smell receptors, Leffler believes. “It is a combination of technology and the avalanche dog that will always be effective in finding an avalanche victim.”
Living with someone changes your microbiome, new research shows
Some roommate frustration can be expected, whether it’s a sink piled high with crusty dishes or crumbs where a clean tabletop should be. Now, research suggests a less familiar issue: person-to-person transmission of shared bacterial strains in our gut and oral microbiomes. For the first time, the lab of Nicola Segata, a professor of genetics and computational biology at the University of Trento, located in Italy, has shown that bacteria of the microbiome are transmitted between many individuals, not just infants and their mothers, in ways that can’t be explained by their shared diet or geography.
It’s a finding with wide-ranging implications, yet frustratingly few predictable outcomes. Our microbiomes are an ever-growing and changing collection of helpful and harmful bacteria that we begin to accumulate the moment we’re born, but experts are still struggling to unravel why and how bacteria from one person’s gut or mouth become established in another person’s microbiome, as opposed to simply passing through.
“If we are looking at the overall species composition of the microbiome, then there is an effect of age of course, and many other factors,” Segata says. “But if we are looking at where our strains are coming from, 99 percent of them are only present in other people’s guts. They need to come from other guts.”
If we could better understand this process, we might be able to control and use it; perhaps hospital patients could avoid infections from other patients when their microbiome is depleted by antibiotics and their immune system is weakened, for example. But scientists are just beginning to link human microbiomes with various ailments. Growing evidence shows that our microbiomes steer our long-term health, impacting conditions like obesity, irritable bowel syndrome, type 2 diabetes, and cancer.
Previous work from Segata’s lab and others illuminated the ways bacteria are passed from mothers to infants during the first few months of life during vaginal birth, breastfeeding and other close contact. And scientists have long known that people in close proximity tend to share bacteria. But the factors related to that overlap, such as genetics and diet, were unclear, especially outside the mother-baby dyad.
“If we look at strain sharing between a mother and an infant at five years of age, for example, we cannot really tell which was due to transmission at birth and which is due to continued transmission because of contact,” Segata says. Experts hypothesized that they could be caused by bacterial similarities in the environment itself, genetics, or bacteria from shared foods that colonized the guts of people in close contact.
Strain sharing was highest in mother-child pairs, with 96 percent of them sharing strains, and only slightly lower in members of shared households, at 95 percent.
In Italy, researchers led by Mireia Valles-Colomer, including Segata, hoped to unravel this mystery. They compared data from 9,715 stool and saliva samples in 31 genomic datasets with existing metadata. Scientists zoomed in on variations in each bacterial strain down to the individual level. They examined not only mother-child pairs, but people living in the same household, adult twins, and people living in the same village in a level of detail that wasn’t possible before, due to its high cost and difficulties in retrieving data about interactions between individuals, Segata explained.
“This paper is, with high granularity, quantifying the percent sharing that you expect between different types of social interactions, controlling for things like genetics and diet,” Gibbons says. Strain sharing was highest in mother-child pairs, with 96 percent of them sharing strains, and only slightly lower in members of shared households, at 95 percent. And at least half of the mother-infant pairs shared 30 percent of their strains; the median was 12 percent among people in shared households. Yet, there was no sharing among eight percent of adult twins who lived separately, and 16 percent of people within villages who resided in different households. The results were published in Nature.
It’s not a regional phenomenon. Although the types of bacterial strains varied depending on whether people lived in western and eastern nations — datasets were drawn from 20 countries on five continents — the patterns of sharing were much the same. To establish these links, scientists focused on individual variations in shared bacterial strains, differences that create unique bacterial “fingerprints” in each person, while controlling for variables like diet, demonstrating that the bacteria had been transmitted between people and were not the result of environmental similarities.
The impact of this bacterial sharing isn’t clear, but shouldn’t be viewed with trepidation, according to Sean Gibbons, a microbiome scientist at the nonprofit Institute for Systems Biology.
“The vast majority of these bugs are actually either benign or beneficial to our health, and the fact that we're swapping and sharing them and that we can take someone else's strain and supplement or better diversify our own little garden is not necessarily a bad thing,” he says.
"There are hundreds of billions of dollars of investment capital moving into these microbiome therapeutic companies; bugs as drugs, so to speak,” says Sean Gibbons, a microbiome scientist at the Institute for Systems Biology.
Everyday habits like exercising and eating vegetables promote a healthy, balanced gut microbiome, which is linked to better metabolic and immune function, and fewer illnesses. While many people’s microbiomes contain bacteria like C. diff or E. coli, these bacteria don’t cause diseases in most cases because they’re present in low levels. But a microbiome that’s been wiped out by, say, antibiotics, may no longer keep these bacteria in check, allowing them to proliferate and make us sick.
“A big challenge in the microbiome field is being able to rationally predict whether, if you're exposed to a particular bug, it will stick in the context of your specific microbiome,” Gibbons says.
Gibbons predicts that explorations of microbe-based therapeutics will be “exploding” in the coming decades. “There are hundreds of billions of dollars of investment capital moving into these microbiome therapeutic companies; bugs as drugs, so to speak,” he says. Rather than taking a mass-marketed probiotic, a precise understanding of an individual’s microbiome could help target the introduction of just the right bacteria at just the right time to prevent or treat a particular illness.
Because the current study did not differentiate between different types of contact or relationships among household members sharing bacterial strains or determine the direction of transmission, Segata says his current project is examining children in daycare settings and tracking their microbiomes over time to understand the role genetics and everyday interactions play in the level of transmission that occurs.
This relatively newfound ability to trace bacterial variants to minute levels has unlocked the chance for scientists to untangle when and how bacteria leap from one microbiome to another. As researchers come to better understand the factors that permit a strain to establish itself within a microbiome, they could uncover new strategies to control these microbes, harnessing the makeup of each microbiome to help people to resist life-altering medical conditions.