Researchers design a functioning artificial womb

If effective with humans, the device could provide the right environment for extremely premature babies

Researchers have designed an artificial womb-like device that could drastically change the way we care for extremely premature babies. The device, which has been used successfully with lambs, mimics the environment of a real womb. It’s designed to allow critically preterm infants to continue developing as they normally would.

Each year, about 30,000 babies in the US are born critically preterm, spending less than 26 weeks in their mother’s womb. Any birth before 37 weeks is considered premature. With current care practices, infants born as early as 23 weeks have a 30-50 percent chance of survival, but survivors typically face lifelong disability from underdeveloped organs. This has led researchers at the Children’s Hospital of Philadelphia to explore more effective ways to care for preterm infants. The development of this new device brings them much closer to this goal. “We’ve been amazed by how well it’s worked,” said senior author Alan Flake, a fetal surgeon and director of the hospital’s Center for Fetal Research.

The device is designed to approximate the environment of the mother’s uterus as closely as possible. “A fluid environment is critical for fetal development, and we’ve developed a closed system which continuously exchanges amniotic fluid in the same way it’s exchanged in the uterus,” said Flake. The infant’s heart would pump blood via the umbilical cord into an external device that replaces the mother’s placenta, exchanging oxygen and carbon dioxide. Premature infants would be removed at 28 weeks, at which point their chances of surviving under traditional neonatal care drastically increase.

Credit: Children's Hospital of Philadelphia

The device has been tested successfully with lambs, which are a common proxy for human embryos in research. Over 28 days, the lamb embryos continued developing as normal. They showed normal breathing, normal brain function, and normal organ maturation. One of the lambs from the study was raised and is now a year old, and subsequent lambs have also grown and thrived.  “We’ve bottle fed them, we’ve grown them up, and they’re reasonably normal in every respect we can tell. There’s no intelligence test for lambs, but we think they’re pretty smart lambs,” said Flake.

The study’s authors estimate that a similar device may be tested on humans in three to five years. Before that can happen, more animal testing and modifications will need to take place. For one, the system will need to be resized for humans, which are approximately a third the size of the lambs used in the study.

It sounds like the stuff of science fiction, but the researchers say their device is intended to be much more natural than the current best care options for extremely preterm babies. “I don’t want this to be visualized as fetuses hanging on the wall in bags,” added Flake. “That’s not the way this device will look or work.” Instead, the researchers plan for the human version of the device to have a dark interior and an imaging system to allow parents to see their child. They also envision audio recordings that simulate sounds a fetus would normally hear in the womb, like the mother’s heartbeat. “We’ll try to make it an environment that is parent friendly, a much less stressful situation than seeing their fetus on an incubator and exposed bed, having IVs started and experiencing painful and uncomfortable stimuli like bright lights,” said Flake.