Artificial womb may offer hope for tiniest preemies

WASHINGTON Researchers are creating an artificial womb to improve care for extremely premature babies — and remarkable animal testing suggests the first-of-its-kind watery incubation so closely mimics mom that it just might work.

Today, premature infants weighing as little as a pound are hooked to ventilators and other machines inside incubators.

Children’s Hospital of Philadelphia is aiming for a gentler solution, to give the tiniest preemies a few more weeks cocooned in a womblike environment — treating them more like fetuses than newborns in hopes of giving them a better chance of healthy survival.

The researchers created a fluidfilled transparent container to simulate how fetuses float in amniotic fluid inside mom’s uterus, and attached it to a mechanical placenta that keeps blood oxygenated.

In early-stage animal testing, extremely premature lambs grew, apparently normally, inside the system for three to four weeks, the team reported recently.

“We start with a tiny fetus that is pretty inert and spends most of its time sleeping. Over four weeks we see that fetus open its eyes, grow wool, breathe, swim,” said Dr. Emily Partridge, a CHOP research fellow and first author of the study published in Nature Communications.

“It’s hard to describe actually how uniquely awe-inspiring it is to see,” she added.

Human testing still is three to five years away, although the team already is in discussions with the Food and Drug Administration.

“We’re trying to extend normal gestation,” said Dr. Alan Flake, a fetal surgeon at CHOP who is leading the project and considers it a temporary bridge between the mother’s womb and the outside world.

Increasingly hospitals try to save the most critically premature infants, those born before 26 weeks gestation and even those right at the limits of viability — 22 to 23 weeks. Extreme prematurity is a leading cause of infant mortality, and those who do survive frequently have serious disabilities such as cerebral palsy.

The idea of treating preemies in fluid-filled incubators may sound strange, but physiologically it makes sense, said Dr. Catherine Spong, a fetal medicine specialist at the National Institutes of Health.

One of the biggest risks for very young preemies is that their lungs aren’t ready to breathe air, she said.

Doctors hook preemies to ventilators to keep them alive but risk lifelong lung damage.

Flake’s ultimate goal is for the womblike system to support the youngest preemies just for a few weeks, until their organs are mature enough to better handle regular hospital care.