Artificial uterus

Illustration of an artificial womb patented by Emanuel M Greenberg in 1955.

An artificial uterus (or artificial 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, would have many applications. It could be used to assist male or female couples in the development of a fetus.^[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]

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 emphasize 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, oxygen supply and waste disposal

A female may still supply nutrients and dispose of waste products if the artificial uterus is connected to her.^[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%.^[1][5]
• 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]

Bioethical considerations

The development of artificial uteri and ectogenesis raises a number of bioethical and legal considerations.

The artificial uterus has important implications for reproductive rights and the abortion debate. Artificial uteri may expand the range of fetal viability, raising questions about the role that fetal viability plays within abortion law. Within severance theory, for example, abortion rights only include the right to remove the fetus and do not extend to terminate the life of the fetus. If transferring the fetus from a woman's womb to an artificial uterus is possible, the choice to terminate a pregnancy may not necessitate the termination of the fetus.^[8][9]

There are also concerns that children who develop in an artificial uterus may lack "some essential bond with their mothers that other children have."^[10]

In the 1970 book The Dialectic of Sex, feminist Shulamith Firestone wrote that differences in biological reproductive roles are a source of gender inequality. Firestone singled out pregnancy and childbirth, making the argument that an artificial womb would free "women from the tyranny of their reproductive biology."^[11][12]

In fiction

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

• The first work of science fiction to propose the idea of ectogenesis was the science fiction essay Daedalus or Science and the Future by Geneticist J.B.S Haldane.
• 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.^[13]
• 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.
• Though a documentary based on fact, the final scene of the 1974 film Birds Do It, Bees Do It showed a speculative future where human fetuses are grown in artificial wombs, apparently for the vast majority of human reproduction.
• In Marge Piercy's 1976 science fiction novel, Woman on the Edge of Time, babies are grown in artificial uteri.
• 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 plotline is about the first baby born from an artificial 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.
• In Pokémon: The First Movie, Mewtwo was created through artificially bringing a mew fetus to birth through a system of unexplained machines.
• The artificial uterus has made an appearance in the Gundam series: in Gundam Wing, one of the main characters Quatre Raberba Winner 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 video game Hitman franchise, Dr. Ort-Meyer's clones are made out of artificial wombs.
• 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 hybrid, 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.
• In Babylon 5, Lyta Alexander's memories reveal that the Vorlons have been using artificial wombs to grow foetuses of several species, including Humans, Drazi and Centauri, as a way of introducing the gene for telepathy into those species.
• Damian Wayne, Bruce Wayne & Talia al Ghul's son is a product of this and genetic manipulation. Talia hid Damian's existence from his father, until she found it reasonable for her own means. He is currently acting as his father's sidekick Robin and in an alternate future shown to take up his father's title.
• In Eclipse Phase almost all biological bodies are gestated within exo-wombs, allowing for easier genetic manipulation of the fetus and the inclusion of various cybernetic implants from birth.

• In the British comic 2000AD, the character Rogue Trooper was genetically engineered to survive on the incredibly polluted planet Nu Earth, and was grown in an incubation vat.

In mythology

In the Mahabharata, Queen Gandhari of Gandhara (existing on the border between Afghanistan and Pakistan), the wife of King Dhrita-rashtra was unable to deliver a baby though several months elapsed. Meanwhile, her brother-in-law's wife Kunthi delivered 5 babies who were to become Pandavas afterwards. Then Gandhari got jealous of Kunthi and hysterically hit against her own belly resulting in a miscarriage. The embryo disintegrated into 100 pieces. They were then placed in "jars of ghee" (clarified butter) by Saint Veda Vyasa, her father-in-law and grown to term as 100 Kaurava princes.

See also

• Amniotic fluid
• Apheresis
• Ectogenesis
• Embryo space colonization
• Extracorporeal membrane oxygenation
• Hemodialysis
• In vitro fertilisation
• Tissue engineering

References

Further reading

• Coleman, Stephen (2004). The Ethics Of Artificial Uteruses: Implications For Reproduction And Abortion. Burlington, VT: Ashgate Pub. ISBN 978-0-7546-5051-5. 
• Scott Gelfand, ed. (2006). Ectogenesis: Artificial Womb Technology and the Future of Human Reproduction. Amsterdam [u.a.]: Rodopi. ISBN 978-90-420-2081-8.