![Nature Communications Biobag system design](https://upload.wikimedia.org/wikipedia/commons/7/7a/Nature_Communications_Biobag_system_design.jpg)
An artificial womb or artificial uterus is a device that would allow for extracorporeal
pregnancy
Pregnancy is the time during which one or more offspring develops (gestation, gestates) inside a woman, woman's uterus (womb). A multiple birth, multiple pregnancy involves more than one offspring, such as with twins.
Pregnancy usually occur ...
[ by growing a ]fetus
A fetus or foetus (; plural fetuses, feti, foetuses, or foeti) is the unborn offspring that develops from an animal embryo. Following embryonic development the fetal stage of development takes place. In human prenatal development, fetal dev ...
outside the body of an organism that would normally carry the fetus to term.
An artificial uterus
The uterus (from Latin ''uterus'', plural ''uteri'') or womb () is the organ in the reproductive system of most female mammals, including humans that accommodates the embryonic and fetal development of one or more embryos until birth. The ...
, as a replacement organ, would have many applications. It could be used to assist male or female couples in the development of a fetus. This can potentially be performed as a switch from a natural uterus to an artificial uterus, thereby moving the threshold of fetal viability
Fetal viability is the ability of a human fetus to survive outside the uterus. Medical viability is generally considered to be between 23 and 24 weeks gestational age. Viability depends upon factors such as birth weight, gestational age, and the av ...
to a much earlier stage of pregnancy.[ In this sense, it can be regarded as a ]neonatal incubator
A neonatal intensive care unit (NICU), also known as an intensive care nursery (ICN), is an intensive care unit (ICU) specializing in the care of ill or premature newborn infants. Neonatal refers to the first 28 days of life. Neonatal care, as kn ...
with very extended functions. It could also be used for the initiation of fetal development.[ An artificial uterus could also help make ]fetal surgery
Fetal surgery also known as antenatal surgery, prenatal surgery, is a growing branch of maternal-fetal medicine that covers any of a broad range of surgical techniques that are used to treat congenital abnormalities in fetuses who are still i ...
procedures at an early stage an option instead of having to postpone them until term of pregnancy.[
In 2016, scientists published two studies regarding human embryos developing for thirteen days within an ecto-uterine environment. Currently, a 14-day rule prevents human embryos from being kept in artificial wombs longer than 14 days. This rule has been codified into law in twelve countries.
In 2017, fetal researchers at the ]Children's Hospital of Philadelphia
The Children's Hospital of Philadelphia (CHOP) is a children's hospital in Philadelphia, Pennsylvania, with its primary campus located in the University City neighborhood of West Philadelphia in the campus of the University of Pennsylvania. The ...
published a study showing they had grown premature lamb fetuses for four weeks in an extra-uterine life support system.[ ]
Text was copied from this source, which is available under
Creative Commons Attribution 4.0 International License
Components
An artificial uterus, sometimes referred to as an 'exowomb', 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
The placenta is a temporary embryonic and later fetal organ that begins developing from the blastocyst shortly after implantation. It plays critical roles in facilitating nutrient, gas and waste exchange between the physically separate mate ...
, an amniotic tank functioning as the amniotic sac
The amniotic sac, also called the bag of waters or the membranes, is the sac in which the embryo and later fetus develops in amniotes. It is a thin but tough transparent pair of membranes that hold a developing embryo (and later fetus) until s ...
, as well as an umbilical cord
In placental mammals, the umbilical cord (also called the navel string, birth cord or ''funiculus umbilicalis'') is a conduit between the developing embryo or fetus and the placenta. During prenatal development, the umbilical cord is physiologi ...
.
Nutrition, oxygen supply and waste disposal
A woman may still supply nutrients and dispose of waste products if the artificial uterus is connected to her.[ She may also provide immune protection against diseases by passing of ]IgG antibodies
Immunoglobulin G (Ig G) is a type of antibody. Representing approximately 75% of serum antibodies in humans, IgG is the most common type of antibody found in blood circulation. IgG molecules are created and released by plasma B cells. Each IgG ...
to the embryo or fetus.[
''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.][ There is no risk of an immune reaction towards the embryo or fetus that could otherwise arise from insufficient gestational immune tolerance.][ Some individual functions of an artificial supplier and disposer include:
*Waste disposal may be performed through dialysis.][
*For oxygenation of the embryo or fetus, and removal of ]carbon dioxide
Carbon dioxide ( chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is trans ...
, extracorporeal membrane oxygenation (ECMO) is a functioning technique, having successfully kept goat fetuses alive for up to 237 hours in amniotic tanks.[ 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. However, the ]cerebral vasculature
Cerebral circulation is the movement of blood through a network of cerebral arteries and veins supplying the brain. The rate of cerebral blood flow in an adult human is typically 750 milliliters per minute, or about 15% of cardiac output. Arterie ...
and germinal matrix In anatomy, the germinal matrix is a highly cellular and highly vascularized region in the brain out from which cells migrate during brain development. The germinal matrix is the source of both neurons and glial cells and is most active between 8 an ...
are poorly developed in fetuses, and subsequently, there is an unacceptably high risk for intraventricular hemorrhage
Intraventricular hemorrhage (IVH), also known as intraventricular bleeding, is a bleeding into the brain's ventricular system, where the cerebrospinal fluid is produced and circulates through towards the subarachnoid space. It can result from phys ...
(IVH) if administering ECMO at a gestational age less than 32 weeks. Liquid ventilation
Liquid breathing is a form of respiration in which a normally air-breathing organism breathes an oxygen-rich liquid (such as a perfluorocarbon), rather than breathing air.
By selecting a liquid that is capable of holding large amounts of oxy ...
has been suggested as an alternative method of oxygenation, or at least providing an intermediate stage between the womb and breathing in open air.[
*For artificial nutrition, current techniques are problematic.][ ]Total parenteral nutrition
Parenteral nutrition (PN) is the feeding of nutritional products to a person intravenously, bypassing the usual process of eating and digestion. The products are made by pharmaceutical compounding companies. The person receives a nutritional mix ...
, as studied on infants with severe short bowel syndrome
Short bowel syndrome (SBS, or simply short gut) is a rare malabsorption disorder caused by a lack of functional small intestine. The primary symptom is diarrhea, which can result in dehydration, malnutrition, and weight loss. Other symptoms may in ...
, has a 5-year survival of approximately 20%.[
*Issues related to ]hormonal
A hormone (from the Greek participle , "setting in motion") is a class of signaling molecules in multicellular organisms that are sent to distant organs by complex biological processes to regulate physiology and behavior. Hormones are required f ...
stability also remain to be addressed.[
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
Interspecific pregnancy (literally ''pregnancy between species'', also called interspecies pregnancy or xenopregnancy)Page 126 in: is the pregnancy involving an embryo or fetus belonging to another species than the carrier. Strictly, it excludes ...
.
Uterine wall
In a normal uterus, the myometrium
The myometrium is the middle layer of the uterine wall, consisting mainly of uterine smooth muscle cells (also called uterine myocytes) but also of supporting stromal and vascular tissue. Its main function is to induce uterine contractions.
Struc ...
of the uterine wall
The uterus (from Latin ''uterus'', plural ''uteri'') or womb () is the organ in the reproductive system of most female mammals, including humans that accommodates the embryonic and fetal development of one or more embryos until birth. The ute ...
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. Methods have been considered to connect an artificial placenta and other "inner" components directly to an external circulation.
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).[
There is also potential to grow a placenta using human ]endometrial cell
The endometrium is the inner epithelium, epithelial layer, along with its mucous membrane, of the mammalian uterus. It has a basal layer and a functional layer: the basal layer contains stem cells which regenerate the functional layer. The funct ...
s. In 2002, it was announced that tissue samples from cultured endometrial cells removed from a human donor had successfully grown. 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
In vitro fertilisation (IVF) is a process of fertilisation where an egg is combined with sperm in vitro ("in glass"). The process involves monitoring and stimulating an individual's ovulatory process, removing an ovum or ova (egg or eggs) ...
(IVF) legislation in the United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territori ...
.[
A human placenta may theoretically be transplanted inside an artificial uterus, but the passage of nutrients across this artificial uterus remains an unsolved issue.][
]
Amniotic tank (artificial amniotic sac)
The main function of an ''amniotic tank'' would be to fill the function of the amniotic sac
The amniotic sac, also called the bag of waters or the membranes, is the sac in which the embryo and later fetus develops in amniotes. It is a thin but tough transparent pair of membranes that hold a developing embryo (and later fetus) until s ...
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
Ringer's lactate solution (RL), also known as sodium lactate solution, Lactated Ringer’s, and Hartmann's solution, is a mixture of sodium chloride, sodium lactate, potassium chloride, and calcium chloride in water. It is used for replacing ...
can be used as a substitute for amniotic fluid.
Umbilical cord
Theoretically, in case of premature removal of the fetus from the natural uterus, the natural umbilical cord
In placental mammals, the umbilical cord (also called the navel string, birth cord or ''funiculus umbilicalis'') is a conduit between the developing embryo or fetus and the placenta. During prenatal development, the umbilical cord is physiologi ...
could be used, kept open either by medical inhibition of physiological occlusion, by anti-coagulation as well as by stent
In medicine, a stent is a metal or plastic tube inserted into the lumen of an anatomic vessel or duct to keep the passageway open, and stenting is the placement of a stent. A wide variety of stents are used for different purposes, from expandab ...
ing or creating a bypass for sustaining blood flow between the mother and fetus.[
]
Research and development
Emanuel M. Greenberg (USA)
Emanuel M. Greenberg wrote various papers on the topic of the artificial womb and its potential use in the future.
On 22 July 1954 Emanuel M. Greenberg filed a patent on the design for an artificial womb. The patent included two images of the design for an artificial womb. The design itself included a tank to place the fetus filled with amniotic fluid, a machine connecting to the umbilical cord, blood pumps, an artificial kidney, and a water heater. He was granted the patent on 15 November 1955.
On 11 May 1960, Greenberg wrote to the editors of the American Journal of Obstetrics and Gynecology. Greenberg claimed that the journal had published the article "Attempts to Make an 'Artificial Uterus'", which failed to include any citations on the topic of the artificial uterus. According to Greenberg, this suggested that the idea of the artificial uterus was a new one although he himself had published several papers on the topic.
Juntendo University (Japan)
In 1996, Juntendo University
is a private university in Japan. Its headquarters are on its campus in Bunkyo, Tokyo, for the School of Medicine and in Inzai, Chiba, for the School of Health and Sports Science. The university was established in 1838 for medical and in 1946 ...
in Tokyo developed the extra-uterine fetal incubation (EUFI). The project was led by Yoshinori Kuwabara, who was interested in the development of immature newborns. The system was developed using fourteen goat fetuses that were then placed into artificial amniotic fluid under the same conditions of a mother goat. Kuwabara and his team succeeded in keeping the goat fetuses in the system for three weeks. The system, however, ran into several problems and was not ready for human testing. Kuwabara remained hopeful that the system would be improved and would later be used on human fetuses.
Children's Hospital of Philadelphia
In 2017, researchers at the Children's Hospital of Philadelphia
The Children's Hospital of Philadelphia (CHOP) is a children's hospital in Philadelphia, Pennsylvania, with its primary campus located in the University City neighborhood of West Philadelphia in the campus of the University of Pennsylvania. The ...
were able to further develop the extra-uterine system. The study uses fetal lambs which are then placed in a plastic bag filled with artificial amniotic fluid. The system consist in 3 main components: a pumpless arteriovenous circuit, a closed sterile fluid environment and an umbilical vascular access. Regarding the pumpless arteriovenous circuit, the blood flow is driven exclusively by the fetal heart, combined with a very low resistance oxygenator to most closely mimic the normal fetal/placental circulation. The closed sterile fluid environment is important to ensure sterility. Scientists developed a technique for umbilical cord vessel cannulation that maintains a length of native umbilical cord (5–10 cm) between the cannula tips and the abdominal wall, to minimize decannulation events and the risk of mechanical obstruction.[E. Partridge, M. Davey1 An extra-uterine system to physiologically support the extreme premature lamb. Nature communications 2017] The umbilical cord of the lambs are attached to a machine outside of the bag designed to act like a placenta and provide oxygen and nutrients and also remove any waste. The researchers kept the machine "in a dark, warm room where researchers can play the sounds of the mother's heart for the lamb fetus." The system succeeded in helping the premature lamb fetuses develop normally for a month. Indeed, scientists have run 8 lambs with maintenance of stable levels of circuit flow equivalent to the normal flow to the placenta. Specifically, they have run 5 fetuses from 105 to 108 days of gestation for 25–28 days, and 3 fetuses from 115 to 120 days of gestation for 20–28 days. The longest runs were terminated at 28 days due to animal protocol limitations rather than any instability, suggesting that support of these early gestational animals could be maintained beyond 4 weeks. Alan Flake, a fetal surgeon at the Children's Hospital of Philadelphia hopes to move testing to premature human fetuses, but this could take anywhere from three to five years to become a reality. Flake, who led the study, calls the possibility of their technology recreating a full pregnancy a "pipe dream at this point" and does not personally intend to create the technology to do so.
Eindhoven University of Technology (NL)
Since 2016, researchers of TU/e and partners aim to develop an artificial womb, which is an adequate substitute for the protective environment of the maternal womb in case of premature birth, preventing health complications. The artificial womb and placenta will provide a natural environment for the baby with the goal to ease the transition to newborn life. The perinatal life support (PLS) system will be developed using breakthrough technology: a manikin will mimic the infant during testing and training, advanced monitoring and computational modeling will provide clinical guidance.
The consortium of 3 European universities working on the project consists out of Aachen, Milaan and Eindhoven. In 2019 this consortium was granted a subsidy of 3 million euro, and a second grant of 10 million is in progress.
Together, the PLS partners provide joint medical, engineering, and mathematical expertise to develop and validate the Perinatal Life Support system using breakthrough simulation technologies. The interdisciplinary consortium will push the development of these technologies forward and combine them to establish the first ex vivo fetal maturation system for clinical use. This project, coordinated by the Eindhoven University of Technology brings together world-leading experts in obstetrics, neonatology, industrial design, mathematical modelling, ex vivo organ support, and non-invasive fetal monitoring. This consortium is led by professor Frans van de Vosse and Professor and doctor Guid Oei. in 2020 the spin off Juno Perinatal Healthcare has been set up by engineers Jasmijn Kok and Lyla Kok, assuring valorisation of the research done. More information about the spin off can be found here;
More information about the project of the technical universities and its researchers can be found here:
Weizmann Institute of Science (Israel)
In 2021, the Weizmann Institute of Science
The Weizmann Institute of Science ( he, מכון ויצמן למדע ''Machon Vaitzman LeMada'') is a public research university in Rehovot, Israel, established in 1934, 14 years before the State of Israel. It differs from other Israeli unive ...
in Israel built a mechanical uterus and grew mouse embryos outside the uterus for several days. This device was also used in 2022 to nurture mouse stem cells for over a week and grow synthetic embryos from stem cells.
Philosophical considerations
Bioethics
The development of artificial uteri and ectogenesis raises bioethical
Bioethics is both a field of study and professional practice, interested in ethical issues related to health (primarily focused on the human, but also increasingly includes animal ethics), including those emerging from advances in biology, m ...
and legal considerations, and also has important implications for reproductive rights
Reproductive rights are legal rights and freedoms relating to reproduction and reproductive health that vary amongst countries around the world. The World Health Organization defines reproductive rights as follows:
Reproductive rights rest o ...
and the abortion debate
The abortion debate is a longstanding, ongoing controversy that touches on the moral, legal, medical, and religious aspects of induced abortion. In English-speaking countries, the debate most visibly polarizes around adherents of the self-describ ...
.
Artificial uteri may expand the range of fetal viability
Fetal viability is the ability of a human fetus to survive outside the uterus. Medical viability is generally considered to be between 23 and 24 weeks gestational age. Viability depends upon factors such as birth weight, gestational age, and the av ...
, raising questions about the role that fetal viability plays within abortion law
Abortion laws vary widely among countries and territories, and have changed over time. Such laws range from abortion being freely available on request, to regulation or restrictions of various kinds, to outright prohibition in all circumstances ...
. Within severance theory, for example, abortion rights only include the right to remove the fetus, and do not always extend to the termination of the fetus. If transferring the fetus from a woman's womb to an artificial uterus is possible, the choice to terminate a pregnancy in this way could provide an alternative to aborting the fetus.
There are also theoretical concerns that children who develop in an artificial uterus may lack "some essential bond with their mothers that other children have".
Gender equality and LGBT
In the 1970 book ''The Dialectic of Sex
''The Dialectic of Sex: The Case for Feminist Revolution'' is a 1970 book by the radical feminist activist Shulamith Firestone. Written over a few months when Firestone was 25, it has been described as a classic of feminist thought.
Firestone a ...
'', feminist Shulamith Firestone
Shulamith Bath Shmuel Ben Ari Firestone (born Feuerstein; January 7, 1945 – August 28, 2012) was a Canadian-American radical feminist writer and activist. Firestone was a central figure in the early development of radical feminism and second-w ...
wrote that differences in biological reproductive roles are a source of gender inequality
Gender inequality is the social phenomenon in which men and women are not treated equally. The treatment may arise from distinctions regarding biology, psychology, or cultural norms prevalent in the society. Some of these distinctions are empi ...
. Firestone singled out pregnancy and childbirth, making the argument that an artificial womb would free "women from the tyranny of their reproductive biology."
Arathi Prasad argues in her column on ''The Guardian
''The Guardian'' is a British daily newspaper. It was founded in 1821 as ''The Manchester Guardian'', and changed its name in 1959. Along with its sister papers ''The Observer'' and ''The Guardian Weekly'', ''The Guardian'' is part of the Gu ...
'' in her article "How artificial wombs will change our ideas of gender, family and equality" that "It will ..give men an essential tool to have a child entirely without a woman, should they choose. It will ask us to question concepts of gender and parenthood." She furthermore argues for the benefits for same-sex couples: "It might also mean that the divide between mother and father can be dispensed with: a womb outside a woman’s body would serve women, trans women and male same-sex couples equally without prejudice."
See also
* Amniotic fluid
* Apheresis
Apheresis ( ἀφαίρεσις (''aphairesis'', "a taking away")) is a medical technology in which the blood of a person is passed through an apparatus that separates out one particular constituent and returns the remainder to the circulation ...
* ''Brave New World
''Brave New World'' is a dystopian novel by English author Aldous Huxley, written in 1931 and published in 1932. Largely set in a futuristic World State, whose citizens are environmentally engineered into an intelligence-based social hiera ...
''
* Ectogenesis
Ectogenesis (from the Greek ''ἐκτός'', "outside," and ''genesis'') is the growth of an organism in an artificial environment outside the body in which it would normally be found, such as the growth of an embryo or fetus outside the mother's ...
* Embryo space colonization
Embryo space colonization is a theoretical interstellar space colonization concept that involves sending a robotic mission to a habitable terrestrial planet, dwarf planet, minor planet or natural satellite transporting frozen early-stage human ...
* Extracorporeal membrane oxygenation
* Hemodialysis
Hemodialysis, also spelled haemodialysis, or simply dialysis, is a process of purifying the blood of a person whose kidneys are not working normally. This type of dialysis achieves the extracorporeal removal of waste products such as creatinin ...
* In vitro fertilisation
In vitro fertilisation (IVF) is a process of fertilisation where an egg is combined with sperm in vitro ("in glass"). The process involves monitoring and stimulating an individual's ovulatory process, removing an ovum or ova (egg or eggs) ...
* Male pregnancy
Male pregnancy is the incubation of one or more embryos or fetuses by organisms of the male sex in some species. Most species that reproduce by sexual reproduction are heterogamous—females producing larger gametes (ova) and males producing sma ...
* Postgenderism
Postgenderism is a social, political and cultural movement which arose from the eroding of the cultural, psychological, and social role of gender, and an argument for why the erosion of binary gender will be liberatory.
Postgenderists argue ...
* Tissue engineering
Tissue engineering is a biomedical engineering discipline that uses a combination of cells, engineering, materials methods, and suitable biochemical and physicochemical factors to restore, maintain, improve, or replace different types of biolog ...
References
Further reading
*
*
{{DEFAULTSORT:Artificial Uterus
Hypothetical technology
Obstetrics
Emerging technologies
Uterus
Womb
The uterus (from Latin ''uterus'', plural ''uteri'') or womb () is the organ in the reproductive system of most female mammals, including humans that accommodates the embryonic and fetal development of one or more embryos until birth. The ut ...