Biobags for extreme prematurity?

The newsfeeds have been abuzz this week about premature lambs gestated in part in biobags by researchers at The Children’s Hospital of Philadelphia. See “An extra-uterine system to physiologically support the extreme premature lamb” here.  The lamb has provided a model for much of our understanding of fetal and neonatal development in humans (see articles here and here for examples).  Therefore, the news of a method to gestate fetal lambs ex utero for up to four weeks generated a good amount of excitement.

The “single most important cause of death in the first month of life” for human infants is prematurity.  “About one percent of all infants” born in the U. S. are premature according to Dr. Alan Flake (video here).  Extreme prematurity in human infants is defined as less than 28 weeks gestational age.

Especially challenging is the plight of infants born at 23-24 weeks, and this is the focus of the research by the Children’s Hospital of Philadelphia group, according to the video at Nature World News. Fetal surgeon Flake describes the biobag as “a ‘bridge’ between the womb and the outside world.”

Application of the biobag technology to humans is on the horizon, but not yet available. The goals of the Philadelphia group appear laudable. There are often, however, unintended consequences of technology development. One potential possibility appears at the end of the discussion in the Nature article:

Finally, our system offers an intriguing experimental model for addressing fundamental questions regarding the role of the mother and placenta in fetal development. Long-term physiologic maintenance of a fetus amputated from the maternal–placental axis has now been achieved, making it possible to study the relative contribution of this organ to fetal maturation.

The role of the mother in fetal human development cannot be wholly replicated by the experience of the ewe and the fetal sheep. Could “amputating” the fetal human from his/her maternal-placental axis (i.e., mother) become a casual affair, or be done in order to study the effects of such amputation?  Could this “therapy” eventually become a “reproductive choice”? That is, once the procedure is available, could parents choose ectogenesis over in utero somatogenesis?


— D. Joy Riley, M.D., M.A., is executive director of The Tennessee Center for Bioethics & Culture.