The Biobag may not look much like a womb, but it contains the same key parts: a clear plastic bag that encloses the fetal lamb and protects it from the outside world, like the uterus would; an electrolyte solution that bathes the lamb similarly to the amniotic fluid in the uterus; and a way for the fetus to circulate its blood and exchange carbon dioxide for oxygen.

Prematurity is the leading cause of death for newborns Prematurity is the leading cause of death for newborns. In the US, about 10 percent of babies are born prematurely — which means they were born before they reach 37 weeks of pregnancy. About 6 percent, or 30,000 of those births, are considered extremely premature, which means that they were born at or before the 28th week of pregnancy.

To solve this problem, Flake and his colleagues created a pumpless circulatory system. They connected the fetus’s umbilical blood vessels to a new kind of oxygenator, and the blood moved smoothly through the system. Smoothly enough, in fact, that the baby’s heartbeat was sufficient to power blood flow without another pump.