Artificial uterus

An artificial uterus (or womb) is a theoretical device that would allow for extracorporeal pregnancy or extrauterine fetal incubation (EUFI)^[1] by growing an embryo or fetus outside of the body of a female organism that would normally internally carry the embryo or fetus to term.

An artificial uterus, as a replacement organ, could be used to assist women with damaged or diseased uteri to bring the fetus to term.^[1] This can potentially be performed as a switch from a natural uterus to an artificial uterus, thereby moving the threshold of fetal viability to a much earlier stage of pregnancy.^[1] In this sense, it can be regarded as a neonatal incubator with very extended functions. Also, it can potentially be used for initiation of fetal development.^[1] Furthermore, it could avail for performing, for example, fetal surgery procedures at an early stage instead of having to postpone them until term of pregnancy.^[1]

1 Components
2 Potential for controversy
3 In fiction
4 See also
5 References
6 External links

Components

An artificial uterus would have to provide nutrients and oxygen to nurture a fetus, as well as dispose of waste material. The scope of an artificial uterus (or "artificial uterus system" to emphasis a broader scope) may also include the interface serving the function otherwise provided by the placenta, an amniotic tank functioning as the amniotic sac, as well as an umbilical cord.

Nutrition and oxygen supply and waste disposal

A human may still supply nutrients and dispose of waste products if the artificial uterus is connected to her (or, potentially, him).^[1] Also, it may provide immune protection against diseases by passing of IgG antibodies to the embryo or fetus.^[1]

Artificial supply and disposal have the potential advantage of allowing the fetus to develop in an environment that is not influenced by the presence of disease, environmental pollutants, alcohol, or drugs which a human may have in the circulatory system.^[1] Also, there is no risk of an immune reaction towards the embryo or fetus that could otherwise arise from insufficient gestational immune tolerance.^[1] Following are aspects of individual functions of an artificial supplier and disposer:

Waste disposal may be performed through dialysis.^[1]
For oxygenation of the embryo or fetus, and removal of carbon dioxide, extracorporeal membrane oxygenation (ECMO) is a functioning technique, having successfully kept goat fetuses alive for up to 237 hours in amniotic tanks.^[2] ECMO is currently a technique used in selected neonatal intensive care units to treat term infants with selected medical problems that result in the infant's inability to survive through gas exchange using the lungs.^[3] However, the cerebral vasculature and germinal matrix are poorly developed in fetuses, and subsequently, there is an unacceptably high risk for intraventricular hemorrhage (IVH) if administering ECMO at a gestational age less than 32 weeks.^[4] Liquid ventilation has been suggested as an alternative method of oxygenation, or at least providing an intermediate stage between the womb and breathing in open air.^[1]
For artificial nutrition, current techniques are problematic.^[1] Total parenteral nutrition, as studied on infants with severe short bowel syndrome, has a 5 year survival of approximately 20%.^[5]^[1]
Issues related to hormonal stability also remain to be addressed.^[1]

Theoretically, animal suppliers and disposers may be used, but when involving an animal's uterus the technique may rather be in the scope of interspecific pregnancy.

Uterine wall

Naturally, the myometrium of the uterine wall functions to expel the fetus at the end of a pregnancy, and the endometrium plays a role in forming the placenta.

An artificial uterus may include components of equivalent function. Also, methods have been considered to connect an artificial placenta and other "inner" components directly to an external circulation.^[1]

Interface (artificial placenta)

An interface between the supplier and the embryo or fetus may be entirely artificial, e.g. by using one or more semipermeable membranes such as is used in extracorporeal membrane oxygenation (ECMO).^[2]

There is also potential to grow a placenta using human endometrial cells. In 2002, it was announced that tissue samples from cultured endometrial cells removed from a human donor had successfully grown.^[6]^[7] The tissue sample was then engineered to form the shape of a natural uterus, and human embryos were then implanted into the tissue. The embryos correctly implanted into the artificial uterus' lining and started to grow. However, the experiments were halted after six days to stay within the permitted legal limits of in vitro fertilisation (IVF) legislation in the United States.^[1]

Also, a human placenta may theoretically be transplanted to inside an artificial uterus, but the passage of nutrients across this artificial uterus remains an unsolved issue.^[1]

Amniotic tank (artificial amniotic sac)

The main function of an amniotic tank would be to fill the function of the amniotic sac in physically protecting the embryo or fetus, optimally allowing it to move freely. It should also be able to maintain an optimal temperature. Lactated Ringer's solution can be used as a substitute for amniotic fluid.^[2]

Umbilical cord

Theoretically, in case of premature removal of the fetus from the natural uterus, the natural umbilical cord could be used, kept open either by medical inhibition of physiological occlusion, by anti-coagulation as well as by stenting or creating a bypass for sustaining blood flow between the mother and fetus.^[1]

Potential for controversy

There would be implications for the ongoing controversy regarding abortion, for example by potentially allowing a woman to terminate a pregnancy very prematurely without ending the life of the fetus. Although the technology does not currently exist to raise an embryo from conception to full development outside of a human body, the possibility of such technology raises questions with respect to cloning as well. The elimination of the need for a living uterus would make cloning easier to carry out and yet harder for legal authorities to track. At the same time, the capacity to raise an unwanted fetus apart from the mother would allow the option of fetus adoption, but might raise concerns with respect to children born with no connection to a parent. Some pro-life groups argue that this would allow a father to have a choice in whether to carry a pregnancy to term.

In fiction

The use of the artificial uterus has played a significant role in science fiction:

The most famous depiction was by Aldous Huxley in his 1932 novel, Brave New World. In Huxley's dystopian future, children are grown in artificial wombs before being decanted into the world. It described a centrifugal pump that kept a liquid of hog's stomach extract and fetal foal’s liver moving over the placenta and driving it through a synthetic lung and waste product filter. This approach is not applicable to clinical medicine because a placenta attached to a uterus is not detachable as a viable organ.^[8]
A far-future version of artificial reproduction was featured in the Arthur C. Clarke novel The City and the Stars (1956) where the citizens of Diaspar, the ultimate city, emerge from the Hall of Creation as young adults, live for 1,000 years, then return to the Hall of Creation where their chosen memories are stored and the people disincarnated. At some future time, determined by the Central Computer, they will be embodied again.
A scenario similar to Huxley's is true for Logan's Run, where embryos are extracted from impregnated women to be grown in meccano-breeders by a computer-controlled life-support system.
Philip K. Dick discusses synthetic wombs in his novel The Divine Invasion.
In Frank Herbert's Dune, axlotl tanks are semi-artificial uteri, women turned into biological factories used to create ghola clones and later the spice melange.
In Frank Herbert's 1966 novel Destination:Void plants are bio-engineered to serve as wombs.
In Star Wars: Episode II on the planet Kamino a vast complex makes hundreds of thousands of human clones. It has revolving hubs of laboratory flasks (artificial uteri) containing developing embryos in nutrient solution. They will serve as soldiers for the Republic and to aid the Jedi, who would otherwise be largely outnumbered against the separatist droid armies.
The 1982 movie Tomorrow's Child[1] plotline is about the first baby born from an articial uterus.
In the short-lived 1990s science fiction television series Space: Above and Beyond, the InVitros are a genetically engineered race of people gestated in large laboratory flasks that serve as artificial uteri.
The 1999 movie The Matrix also features the artificial gestation of humans.
The artificial uterus has made an appearance in the Gundam series: in Gundam Wing, one of the main characters Qautre Rababa has 29 sisters that were born from artificial uterus; in Gundam SEED, Kira Yamato is designated the Ultimate Coordinator because he was grown from an artificial uterus.
In the NOW Comics The Terminator comic book series in the 1980s, John Connor's resistance forces utilize artificial uteri to continue human reproduction so that the women in their fighting force do not need to be immobilized by pregnancy.
In David Weber's Honorverse series, fetuses are routinely "tubed" in artificial uterus. Some characters, such as Allison Harrington, refrain from using this option because of moral scruples.
In Lois McMaster Bujold's Vorkosigan Saga, artificial uteri, called uterine replicators are widely used, and body births are considerably out of favor on most technologically advanced worlds, to the extent that Miles Vorkosigan disgusts some Cetagandan women by mentioning that his cousin Ivan was born from his mother's body. Miles was himself gestated in a uterine replicator. Ethan of Athos features an all-male world in which men use artificial uteri to reproduce. Children are grown in and birthed from uterine replicators.
In The Island, cloned humans are grown to adults in artificial uteri to harvest organs.
In Neon Genesis Evangelion, Ayanami Rei is cloned from Ikari Yui and grown through some method of artificial reproduction. Much of the pseudo-technology in this series is a product of utilizing artificial propagation.
In the anime Ergo Proxy, artificial wombs are featured, which are the origin of all inhabitants of the dome city Romdo.
In the Battletech Universe, almost every warrior of each of the Clan factions is born in an artificial uteri. In development they undergo a process that ensures their complete genetic health. They call themselves Truebirths, and feel they are superior to all who were born naturally, whom they call Freebirths.
In Kyle XY Kyle and Jessi are grown in an artificial womb created by Adam Baylin - Kyle's Genetic Donator.
In the 1995 movie Species, Sil, an alien-human hybrid, is grown in an artificial womb.
In the 2009 movie Splice, Dren, an animal-human hydrid, is also grown in an artificial womb.
In the 2009 movie Avatar, The Avatars are grown in artificial amnio tanks during the travel time to Pandora.
In 2011 Book Wombs, Unoccupied space craft equipped with artificial wombs are dispatched to find and inhabit new planets.
In The Naked Sun, a 1957 novel by Isaac Asimov, chapter 11, we find that every fetus on planet Solaria is grown in such devices starting from one month after conception.

References

^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ ^o ^p ^q ^r Bulletti, C.; Palagiano, A.; Pace, C.; Cerni, A.; Borini, A.; De Ziegler, D. (2011). "The artificial womb". Annals of the New York Academy of Sciences 1221: 124–128. doi:10.1111/j.1749-6632.2011.05999.x. PMID 21401640. edit
^ ^a ^b ^c Sakata M, Hisano K, Okada M, Yasufuku M (May 1998). "A new artificial placenta with a centrifugal pump: long-term total extrauterine support of goat fetuses". J. Thorac. Cardiovasc. Surg. 115 (5): 1023–31. PMID 9605071.
^ Bautista-Hernandez, V.; Thiagarajan, R. R.; Fynn-Thompson, F.; Rajagopal, S. K.; Nento, D. E.; Yarlagadda, V.; Teele, S. A.; Allan, C. K. et al. (2009). "Preoperative Extracorporeal Membrane Oxygenation as a Bridge to Cardiac Surgery in Children with Congenital Heart Disease". The Annals of Thoracic Surgery 88 (4): 1306–1311. doi:10.1016/j.athoracsur.2009.06.074. PMID 19766826. edit
^ Alan H. Jobe, MD, PhD. Post-conceptional age and IVH in ECMO patients. RadiologySource Volume 145, Issue 2, Page A2 (August 2004). PII: S0022-3476(04)00583-9. doi:10.1016/j.jpeds.2004.07.010.
^ Spencer AU, Neaga A, West B, et al. (September 2005). "Pediatric short bowel syndrome: redefining predictors of success". Ann. Surg. 242 (3): 403–9; discussion 409–12. PMC 1357748. PMID 16135926. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1357748. (mean follow-up time was 5.1 years)
^ IVF.org - Center for Reproductive Medicine and Infertility, New York, NY
^ Weill Cornell Research
^ Development of an Artificial Placenta Nobuya Unno. Year 2000