An artificial womb resembling a plastic bag has been used to keep premature lambs alive for four weeks outside of their own mothers' wombs and could one day be applied to premature babies.

The sealed bag, made of polythene, contains amniotic fluid to provide all the nutrients and protection needed for growth and an interface delivering oxygen just as an umbilical cord would, and exchanging gases just like a placenta.

The system works to mimic the environment of a natural womb, and the team hopes to one day adapt the technology for use with premature babies.

"We've developed a system that, as closely as possible, reproduces the environment of the womb and replaces the function of the placenta," said  the research lead.

"This, in theory, should allow support of premature infants," lead said, adding that his team's goal is to "meet the unmet need of extreme prematurity."

Globally, more than one in 10 pregnancies will end in preterm birth. In babies born preterm, the chance of survival at less than 23 weeks is almost zero, while at 23 weeks it is 15%, at 24 weeks 55% and at 25 weeks about 80%, according to UK maternal and fetal research charity Tommy's.

The team hopes its new system may improve survival rates among this group of babies in the future but acknowledges that it will take at least a decade.

https://www.nature.com/articles/ncomms15112