Apr 25, 2017

Artificial womb keeps lambs alive for weeks

Partridge et al. Nature Communications 2017.

An artificial womb can keep premature lambs alive for four weeks and support normal growth and development, a new report shows. The researchers hope to apply the approach to human infants.

Why it matters: 30,000 babies are born prematurely (before 26 weeks of gestation) in the U.S. each year. Chances for survival — typically 30 to 50 percent — have improved for infants born early, but they can experience long-term health issues like chronic lung disease and delays in physical and cognitive development.

How it works: The system developed by researchers at the Children's Hospital of Philadelphia mimics a woman's uterus. The fetus is placed in a plastic film bag filled with synthetic amniotic fluid and its umbilical cord is connected to a machine that oxygenates the lamb's blood and returns it and nutrients to the fetus.

Key features: The animal's heart pumps the blood through the system rather than a machine, which can strain an underdeveloped heart. Instead of air, the lungs receive liquid like they do in the womb. Open air incubators that are currently used can arrest lung development and potentially expose infants to pathogens.

What's new: Previous systems kept critically premature animals alive for a few days outside their mother's body. In the study with eight lambs equivalent in gestation to a human fetus at 23 weeks, the animals survived for up to four weeks inside the artificial womb. Their lungs, brains and other organs developed normally and they physically matured, gaining weight and growing wool.

What's next: The researchers are currently working on a preclinical study with the FDA and, if approved, anticipate the device could be tested in hospitals in 3 to 5 years. But major hurdles exist, including determining if a human umbilical cord can be successfully connected, devising the amniotic fluid and assessing the ultimate long-term effects of the approach.

Our thought bubble: By essentially adding an intermediate, artificial stage of development, the technology could open up thorny ethical questions about when a baby is technically born and for how long a fetus could — and should — be raised outside the womb.

Go deeper