Artificial Wombs Grow Lambs — and Could Save Babies’ Lives

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by Anita Carey  •  •  April 27, 2017   

Prematurity is #1 cause of infant death

PHILADELPHIA (Church - Scientists are developing an artificial womb with the aim of helping premature, possibly non-viable babies survive. Latest developments include the successful growth of premature lambs inside what researchers are calling a "Biobag."

Members of the Children's Hospital of Philadelphia published a report Tuesday showing positive results of their tests using the Biobag. According to the report, "fetal lambs that are developmentally equivalent to the extreme premature human infant can be physiologically supported in this extra-uterine device for up to 4 weeks."

The fluid incubator they've created mimics the environment inside the womb. The lambs, taken prematurely from their mother, were each placed inside a plastic sac filled with synthetic amniotic fluid. The water temperature was regulated, and the lamb's umbilical cord was attached to an oxygenator that delivered nutrients to the animal. 

Several of the lambs developed normally for four weeks: "Animals opened their eyes, became more active, had apparently normal breathing and swallowing movements, grew wool and clearly occupied a greater proportion of space within the bags," the report stated.

Prematurity remains the top cause of infant mortality. As many as half of all infants born at 24 weeks die, and up to 90 percent experience illness owing to lung and organ immaturity. 

"With each week of advancing gestation, the morbidity and mortality progressively decrease," says Dr. Alan Flake, director of the Center for Fetal Research at Children's Hospital Philadelphia. "[O]nce you get to 27 weeks, most of the risk related to prematurity is gone."    

The concept for this artificial system is not new, with research dating back to the 1950s. Building on previous efforts, the team began thinking about the needs of the unborn instead of those of newborns. They developed a blood circulation and aeration device that allows the baby's heart to circulate the blood as opposed to a system that forces blood through it, a system that has usually led to heart failure.

Flake notes: "Every step is directed towards normality. Every obstacle we've encountered we've been able to overcome by turning to 'mother nature's normal physiology and trying to replicate it."

The second component for the system is a plastic bag system filled with an artificial amniotic fluid to incubate the preterm infant in a similar environment to a womb. Fetal physiologist and researcher Marcus G. Davey designed the fluid delivery system said "fetal lungs are designed to function in fluid, and we simulate that environment here, allowing the lungs and other organs to develop, while supplying nutrients and growth factors."

While research into the causes of premature births continues, all of the causes are not fully understood and cannot be completely prevented. Even so-called "normal" pregnancies have led to preemies.

The World Health Organization estimates that worldwide, 15 million babies are born prematurely each year with one million of them dying. In the United States alone, 1 in 10 babies is born prematurely and about 30,000 are born before 26 weeks and considered extremely premature.

For those born at 23-weeks gestation, statistics show 70 percent die from complications. Of those that do go home, 49 percent have moderate to severe disabilities and only 13 percent are free of any disability. The researchers stated the leading cause of cerebral palsy is premature birth. 

Babies born extremely prematurely face numerous health risks and are more likely to be hospitalized or die in infancy. Immediate concerns for preemies can be maintaining body temperature, a weak immune system, breathing problems, bleeding in the brain, blood abnormalities such as anemia and jaundice and metabolic conditions stemming from liver immaturity. Long-term conditions can include dental, hearing or vision problems, mental retardation or learning disabilities, as well as sudden infant death syndrome or SIDS. 

During the experimentation with the lambs inside the Biobag, many of the short-term problems were alleviated, including temperature control and susceptibility to infection. Additionally, lung, brain and organ development continued at a rate comparable to normal lambs. 

The research team is currently working with the Food and Drug Administration and hope to begin clinical trials with the artificial womb within one to two years. 



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Anita Carey

Anita Carey is a staff writer for