Grow Your Fetuses Outside Your Body in the Biobag

Zebedia R. Quader

Freshman

School of Life Sciences

Independent University, Bangladesh

March 8th, 2018

We all have heard about Mary and her little lamb, but have you heard that Mary can now watch her little lambs grow in front of her own eyes? Some researchers at the Children’s Hospital of Philadelphia (CHOP) located in Pennsylvania, recently came up with what they have dubbed as the biobag. In this biobag, they saw eight little lambs grow just like they would in their mother’s uterus or womb. What is this biobag? It is a transparent plastic bag filled with artificial amniotic fluid and blood just like a natural womb.

The CHOP team, collected surplus materials from hospitals, such as those required for extracorporeal membrane oxygenation (ECMO) which oxygenates the blood of very ill infants. The ECMO equipment was collected to attempt to provide oxygen to the lambs just like it would in a baby.

To ease into the process, the researchers first placed the lambs into early biobag prototypes only a little before they should be delivered naturally. These early versions made use of circulating artificial amniotic fluid with infused electrolytes, and were connected to an oxygenator. Only one animal lived for 108 hours, and that too with complications. This was not enough.

Over the next few months, they worked on refining their technique with the additional help of surgeons. A major change that they settled on involved using non-circulating artificial amniotic fluid; this basically meant that the fluid would enter through one tube and leave through another, and the exiting fluid would not reenter. They also connected the oxygenation unit to the fetus lamb directly via the umbilical cord, allowing the fetus’s heart to control the circulation.

The completed version of the biobag was able to allow development of premature fetuses (eight of them) for four weeks, until they were ready for “delivery”. Sheep pregnancies last around five months, so being able to facilitate the final month of development of the fetus outside the mother’s womb is a ground-breaking advancement. These lambs look, behave, eat, and respond like naturally born lambs, short of some minor side-effects in a few of them.  It is nothing short of a miracle that a little piece of plastic could replicate the function of a womb.

Schematic diagram of the set-up. Nature Communications

When the results of this study were published, the science world raged into a storm. Lots of praises resounded, but there were more critical voices as well, mostly surrounding ethical implications of the study.  People were concerned about how being able to develop babies outside the womb could erode the mother-baby relationship, or allow experimentation. The researchers responded that the biobag is for premature animals and babies only, and could not support embryos from inception. And even if it were possible, one might argue that surrogacy already exists, and there are regulations for conducting research on embryos. The biobag in its current state, and if perfected for human babies, would only reduce the mortality rate of premature babies, which often suffer from serious, life-threatening complications. Who could oppose that?

Now, lambs and human babies are not the same but the researchers expect the process to be ready for human trials by 2019. If successful, it could revolutionize maternal-fetal medicine. But it is going to be a lot of work.

Flake, the head researcher for the study, has said in an interview, “I’m still blown away, whenever I’m down looking at our lamb. I think it’s just an amazing thing to sit there and watch the fetus on this support acting like it normally acts in the womb... It’s a really awe-inspiring endeavor to be able to continue normal gestation outside of the mom.”

Zebedia writes,

"With a curious mind, microbiology has provided me with the ultimate source of entertainment, perhaps for life."