Philadelphia doctors have kept fetal lambs alive in a uterus-like plastic sack for weeks, a technological leap toward caring for premature infants that also raises questions over how early babies might be considered viable outside the womb.
The device, eyed as an improvement over incubators, kept fetal animals alive using a sterile, temperature-controlled plastic bag filled with amniotic fluid.
The gestational age of the animals was equivalent to a human fetus of 22 or 23 weeks, about the earliest a human baby can be born and expected to survive outside the womb. A full-term baby is born at 40 weeks.
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,” says Emily Partridge, a research fellow at Children’s Hospital of Philadelphia, whose description of the device was published today in Nature Communications.