WASHINGTON (AP) — 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 womb-like environment — treating them more like fetuses than newborns in hopes of giving them a better chance of h...