The artificial womb contains a mixture of warm water and added salts, similar to an amniotic fluid with a machine hooked to the umbilical cord to deliver oxygen. After 28 days, when their lungs had matured enough, the lambs were released so they could start breathing air.

This system is designed to closely mimic the womb in order to help very premature newborns develop their lungs and other organs since ventilators can damage lung development.