Scientists develop device to mimic the womb
Science | The system could save premature babies, but comes with big ethical questions
by Kiley Crossland
Posted 4/27/17, 02:54 pm
Researchers have developed a womb-like device they hope can save and improve the lives of extremely premature babies. The device has only been tested on baby lambs so far, but the Children’s Hospital of Philadelphia scientists plan to test it on premature humans in the next few years, according to a study published Tuesday in the journal Nature Communications.
The development shows more promise than any previous attempt to mimic the womb environment for critically preterm babies, but it also raises a host of ethical questions scientists and doctors are struggling to answer, including questions about its effect on the abortion debate.
The extra-uterine system is a plastic bag, called a Biobag, filled with artificial amniotic fluid. It has two tubes that connect to the baby’s umbilical cord. One tube runs to an oxygenator and infuses the baby’s blood with oxygen and nutrients and removes carbon dioxide. The other tube pumps the blood back into the baby’s body using the power of the baby’s own heartbeat.
During the study, infant lambs, placed in the sack within seconds of a cesarean section, were given a drug so they wouldn’t breathe air during delivery and could continue to breathe and swallow amniotic fluid in the Biobag like babies in utero. The researchers placed the Biobags in a warm, dark room and played the sound of the mother’s heartbeat.
So far, researchers have successfully cared for premature baby lambs for up to four weeks in Biobags with unprecedented results.
“They’ve had normal growth,” said Alan Flake, a fetal surgeon and the study leader. “They’ve had normal lung maturation. They’ve had normal brain maturation. They’ve had normal development in every way that we can measure it.”
Extreme prematurity is the leading cause of infant death and illness in the United States. Nearly one-third of all infant deaths and one-half of all cases of cerebral palsy are linked to premature birth, according to the study. Each year, about 30,000 U.S. babies are born before 26 weeks of gestation.
Medical advancements have enabled doctors to care for babies born as early as 22 to 23 weeks of gestation, however the methods they now use to keep those babies alive—incubators with ventilators—cause irreparable damage to underdeveloped organs. Premature lungs are not intended to breathe gas, and even the gentlest ventilators are a shock to the infants’ systems.
But the Biobag researchers hope to present another option, something they see as a “bridge between the mother’s womb and the outside world.”
“If we can develop an extra-uterine system to support growth and organ maturation for only a few weeks, we can dramatically improve outcomes for extremely premature babies,” Flake said.
The Biobag has practical challenges. Hooking up the tubes is hard because the umbilical cord shrinks when it is exposed to oxygen. The amniotic fluid can become contaminated, causing infection, and the baby’s heart sometimes can’t handle the job of pumping the blood through the oxygenator.
There are ethical challenges, as well, including whether the system could cause emotional stress on the baby and whether the lack of human connection could have adverse effects. Others worry the technology could develop and eventually be used to care for babies all the way from embryo to delivery, raising questions of possible coercion.
Scott Gelfand, a bioethicist at Oklahoma State University, told NPR he was concerned employers could require women use “artificial wombs” to avoid pregnancy or insurers could require the device for at-risk pregnancies. “The ethical implications are just so far-reaching,” he said.
But while this development is significant progress, it is not an “artificial womb,” according to John Pierce, a doctor and professor of obstetrics, gynecology, and internal medicine at Liberty University’s College of Osteopathic Medicine. He argued the term “womb” gives the Biobag system too much credit.
“An ‘artificial womb’ implies implantation and growth from the egg and the sperm until delivery,” Pierce said. While the system has shown great promise at taking already developed organs and helping them mature further without the risk of infection, Pierce said there was no way this system was as good as a natural womb, something he called a miraculous environment.
“When I start thinking about the complexity of recreating a womb without complications, it is mind boggling,” Pierce said, noting the things that happen without a mother even directing them in the womb, including the placenta providing the right nutrients in the right amount at the right time during development, the regulation of blood pressure and blood flow, and the ability to fight infection.
Pierce also pointed to the implications of the Biobag’s development on the abortion debate, much of which centers on the ever-changing idea of viability. “If you can end up having a baby born earlier and earlier, but you can electively abort a baby past that date, that gives us pause to say ‘Wait a minute, is that the right thing to do?’”
The team at Children’s Hospital of Philadelphia maintains the Biobag was only developed for premature babies considered viable today.
“I want to make this very clear: We have no intention, and we’ve never had any intention with this technology, of extending the limits of viability further back,” Flake says. “I think when you do that, you open a whole new can of worms.”
Dena Davis, a bioethicist at Lehigh University, told NPR she had similar concerns: “Up to now, we’ve been either born or not born. This would be halfway born, or something like that. Think about that in terms of our abortion politics.”
Flake said the researchers have been interacting with the FDA and hope to take the Biobag to clinical trials one to two years from now.
Kiley is a former WORLD correspondent.