Babies who are born extremely prematurely either don't survive or live with serious lasting disabilities. A group of scientists is hoping to bring the statistics much lower by developing an artificial womb. They have made some initial tests using lamb fetuses with promising results.

A group of scientists from the Children's Hospital of Philadelphia created an artificial womb which enables fetuses to develop normally for about a month.

The device is made up of a clear plastic bag that is filled with a synthetic amniotic fluid and a machine that functions like a placenta and attached to the umbilical cord. The machine is outside the bag and pumps the needed nutrition and oxygen into the fetus and, at the same time, removes the carbon dioxide inside the bag.

The device is placed in a dark and warm room where the researchers play the mother's heartbeat for the fetus to hear. They also monitor the fetal development using ultrasound.

Alan Flake, a fetal surgeon at the hospital and the author of the study said that the whole idea of the artificial womb is to support the normal development of the fetus by re-creating everything that the real womb does.

So far, the scientists have tested it to fetal lambs and hope that as they further develop the device, they will be able to use it on human babies after five years.

When asked why lambs instead of other animals, the scientists said that previous research showed that they are good models for human fetuses.

Just like any new research, the experiment has been met with both praise and criticism.

Those who favored the experiment called the device a technological miracle and that it could help them learn more about how fetuses develop. Critics, on the other hand, said that it raised a lot of ethical issues including the issue whether it would be acceptable to test it on human babies.

Flake said that such ethical concerns need to be balanced with the risks premature babies face, such as severe disabilities and even death.

The study is published in the journal Nature Communications.