By Randall K. O’Bannon, NRL Director of Education & Research
It’s a staple of science fiction, most famously in Huxley’s Brave New World. Rows of bubbling vats of amber liquid holding developing babies of various ages hooked with tubes and wires to nutrients and monitors.
Well, it turns out it doesn’t look exactly like that, but a new experiment done with premature sheep at the Children’s Hospital of Philadelphia written up in the journal Nature Communications shows that the artificial womb may be closer to reality than anyone might have thought.
Instead of a hard vat full of bubbling goo and a whole lot of tubes and wires plugged into a fetal body and brain, the device developed by doctors at the Philadelphia Children’s Hospital is something more like a large sealed zip lock bag, a flexible pouch filled with fluid continuously being exchanged by one entry and one exit tube ensuring that the developing animal has clean, healthy “amniotic” fluid.
According to the research team, the only direct connection to the animal is via an artificial “umbilical artery/vein” connecting to the animal’s own umbilical cord. This provides needed oxygen, nutrients to the animal, removing waste products. The animal’s own heart manages the circulation so as not to overtax the developing organ with excessive pressure.
The aim is to artificially duplicate, as much as possible, the mother lamb’s natural womb environment.
Though still in its early animal testing stages, the experiment appears to have been successful. Six pre-term lambs, living and developing in the artificial environment for as much as a month, “breathing” and swallowing normally, growing wool, opening their eyes, and developing properly functioning nerves and organs.
Some of the animals were humanely killed to allow examination of their brains, organs and other tissues, but others were allowed to live and were bottle fed. Dr. Alan Flake, leader of the project, told the London Telegraph, “They appear to have normal development in all respects.”
The concern and aim of researchers, they write in “An extra-uterine system to physiologically support the extreme premature lamb,” is to provide “a bridge between the mother’s womb and the outside world,” as Dr. Flake told the London Telegraph, for human babies born extremely prematurely before lung and organ formation is complete.
A separate study on prematurity in general appeared in 2015 in the Journal of the American Medical Association. Researchers found that survival rates for premature infants had improved in recent years with better treatment and interventions. By 2012, one-third of babies born at 23 weeks survived, as did 9% of children born at 22 weeks.
If those children could be given the chance to extend their time in the womb an additional four weeks, the 9/8/15 JAMA data suggests that survival rates might jump, going as high as 87% for babies born at 26 weeks and 94% for children born at 27 or 28 weeks. Furthermore, their prospects for being discharged from the hospital without any major problems would also greatly improve.
“Flake says the group hopes to test the device on very premature human babies within three to five years,” according to NPR’s Rob Stein. However a number of hurdles remain.
Though chosen for their similarities at the given stage of development, the development of animal and human fetuses are not identical. Lambs at that stage are larger, and researchers do not know if the umbilical vessels of lambs function exactly the same way as those of the human fetus. The balance of chemicals and fluids in the amniotic fluid will need to be just right, as will the gas exchange and nutrients of the artificial umbilical system.
Something else to consider is the psycho-social impact of being in a biobag for several weeks rather than the warm, tight familiar confines of the mother’s womb.
Moreover sometimes issues that seem relatively straightforward in animal testing turn out to be considerably more complex with humans.
And there are any number of ethical questions which must be addressed.
The authors say that there is nothing in their model that should lead people to believe this technology would be applicable at even earlier stages. Those babies are too fragile for this technology and Dr. Flake told reporters that there was no technology “even on the horizon” to replace a mother’s womb at the earliest stages of fetal development (Telegraph, 4/25/17).
“Flake says his team has no interest in trying to gestate a fetus any earlier than about 23 weeks into pregnancy,” according to Stein.