Researchers from the Children's Hospital of Philadelphia (CHOP) are searching for ways to help premature babies survive. The research is now in the early stages of animal testing where a lamb was placed in an artificial womb to mimic the conditions inside the mother's uterus.

The biobag is filled with amniotic fluid and attached to a placenta that helps keep blood oxygenated. The first attempt appears to be a success as the premature lamb grew successfully inside the artificial womb or the biobag for three to four weeks.

"We start with a tiny fetus that is pretty inert and spends most of its time sleeping. Over four weeks we see that fetus open its eyes, grow wool, breathe, swim," Dr. Emily Partridge, a CHOP research fellow and first author of the study published in Nature Communications, said in an interview with ABC News. "It's hard to describe actually how uniquely awe-inspiring it is to see."

Despite the success of the animal testing, researchers believe that human testing is still three to five years ahead. Nevertheless, the goal is to get there and they are reportedly communicating with the Food and Drug Administration (FDA) in order to conduct future testing. Some experts around the world commented on the successful trial.

"But I would just caution this is pre-clinical and new and experimental data - we're still a long way off being able to use the findings from this work in the neo-natal intensive care unit," Dr. David Tingay, from the Murdoch Children's Research Institute, said in a statement.

Based on the study, the key to making premature babies survive is to treat them like fetuses inside the womb and extend the gestation period, contrary to caring for them in an incubator. Dr. Alan Flake, a fetal surgeon calls it a "bridge" between the womb and the outside world.

Hospitals are trying to develop technologies that can help premature babies born before 26 weeks survive. Failure to develop completely can cause death and in some cases, serious disabilities such as cerebral palsy.

The artificial womb or the biobag helped the lamb develop some of its organs. The lungs, brain and other organs were monitored during testing and they showed increase development during the time inside the artificial womb. The lamb even learned how to swallow during the process.