This Goat Did Not Come From an Artificial Womb

• 
• |
• 
• |
• |
• 19

Not too long ago, baby-in-a-box technology seemed imminent. In the late 1990s, scientists in Japan startled the world with a freestanding artificial womb: an acrylic, fluid-filled incubator. The scientists used it to gestate goats that had been removed prematurely from their mothers' uteruses. Again in the early 2000s, a group of IVF researchers in Manhattan made headlines with custom wombs: They grew endometrial tissue, molded it into a curved shape, and tried to bring human and mouse embryos to term. Neither project made it to fruition. But there was every reason to feel excited by the promises of high-tech womb substitutes, in which human babies might someday come to term. Since then, though, the scientific quest for artificial uteruses has sputtered. Why has it gone thoroughly out of fashion?

In the last five years, scientists have come to believe that the environment of the mother's womb is more, not less, complex and crucial. Across several different fields, research has taken off on the intertwining of mother and embryo, or fertilized egg, that occurs from the very beginning. Psychologists are finding that maternal cues may influence the personality of the developing fetus. Cellular cross-talk between mother and fetus seems to shape normal development and susceptibility to disease. And some IVF scientists have tried to reduce chromosomal abnormalities by incubating fertilized eggs within the mother's body, minimizing the time in a Petri dish. All of this adds up to a sea change in how scientists view the uterus, and makes the idea of bypassing the maternal womb seem nearly impossible. At the beginning of our lives, we apparently need mothers even more than we ever thought.

It's worth revisiting how close scientists thought they were to a brave new no-uterus world to see how clearly scientific attitudes have shifted. The group led by Yosinori Kuwabara in late-'90s Japan managed to keep goat fetuses alive for up to three weeks in a fluid-filled incubator, with an artificial placenta that supplied oxygen and nutrients and removed wastes. Remarkably, several fetuses made it to term (21 weeks for a goat). But they had lung disorders and other abnormalities. Also, they weren't popped into the incubator until a late gestational age. As one expert on preemies told me, if you translate goat time to human time, the fetuses "were practically teenagers" by the time they reached the artificial womb.

The IVF researchers also, fleetingly, boasted seeming success. Concentrating on the beginning of gestation rather than the end, they created tissue-engineered wombs in which fertilized eggs might develop. Led by researcher Hung-Ching Liu at the Center for Reproductive Medicine and Infertility in Manhattan, the group managed to grow human embryos for up to 10 days. Starting in 2002, Liu's team also created artificial mouse uteruses in which they incubated numerous mice. At least one survived almost to term. But ultimately, it died along with the others, some of which had striking physical abnormalities. Blood vessels linking the fetus to the artificial womb had failed to develop normally, Liu said at the time. Since then, she has stopped speaking publicly on the topic. A spokesperson would only confirm that the research "has not been ongoing for several years." (Never mind that in 2005, Liu confidently told a reporter that she expected to have a viable mouse womb in five to 10 years and a human one in "10 years, maybe, or a little more.")