The authors hope the technique can be used to improve survival chances for premature babies.
Scientists have been able to keep premature lambs alive for weeks using an artificial womb that looks like a plastic bag, according to a study published today.
The authors of the study, published in Nature Communications, hope that the new approach will lead to better survival chances for babies born prematurely.
The "artificial womb" used in the study provides everything the foetus needs to continue growing and maturing, including a nutrient-rich blood supply and a protective sac of amniotic fluid. Eight lambs survived for as long as four weeks inside the devices. The gestational age of the animals was equivalent to a human foetus of 22 or 23 weeks, about the earliest a baby can be born and expected to survive outside the womb.
Photo: Children's Hospital of Philadelphia
The animals, which were able to move, open their eyes, and swallow normally, were "born" when researchers removed them from the sacs.
Tests showed they had developed normally and their lung function "essentially caught up to that of a mature infant," said Emily Partridge, a research fellow at Children’s Hospital of Philadelphia, one of the lead authors.
When to be used for humans?
Co-author Dr Marcus Davey, a foetal physiologist, said that the researchers are currently undertaking further animal trials, which they hope to complete within two years, "then move on to first in human use within three to four years." However, associate professor David Tingay, a neonatal researcher at Murdoch Childrens Research Institute, said while this model was the most promising artificial womb yet, it could be a long time before this sort of technology was being used in hospitals.
"[The womb] appears to do what others haven't been able to do, which is to keep the animal alive for a long period of time and show that it's growing normally," he said.
"This is a very promising research finding, which will help us better understand how to support pre-term babies but there's still need for caution and we would be a long way - I would estimate a decade or more - before we would be able use this knowledge in the NICU."
Viability
The study has already raised questions about whether the technology could extend the limits of foetal viability - the ability of a baby to survive apart from its mother - and how this could affect the abortion debate. However, Alan Flake, director of the Philadelphia hospital's Children's Institute for Surgical Science, said the machinery would not be capable of incubating a child for a full nine months - as yet, no technology can replace the earliest stages of development. "There are likely developmental requirements that we cannot replicate earlier in gestation, so we could create developmental abnormalities," he said.
The Children's Hospital of Philadelphia team insists it is not looking to replace mothers or extend the limits of viability - merely to find a better way to support babies who are born too early.
Protecting life
Dr Anthony McCarthy of SPUC said: "While at present, the researchers claim not to be trying to extend viability, in the future, artificial wombs may be used to preserve the lives of human babies previously said to be non-viable. Viability, as opposed to the dignity of all human lives, is variable and dependent on technology. That advanced countries invest in technology to preserve very young babies tells us something about what medical technology is for. It is for protecting life, born and unborn, where this is possible and reasonable. It is not for taking life, viable or otherwise."
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