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placenta

 
Dictionary: pla·cen·ta   (plə-sĕn'tə) pronunciation
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n., pl., -tas, or -tae (-tē).
    1. A membranous vascular organ that develops in female mammals during pregnancy, lining the uterine wall and partially enveloping the fetus, to which it is attached by the umbilical cord. Following birth, the placenta is expelled.
    2. An organ with similar functions in some nonmammalian animals, such as certain sharks and reptiles.
  2. Botany. The part within the ovary of a flowering plant to which the ovules are attached.

[New Latin, from Latin, flat cake, alteration of Greek plakoenta, from accusative of plakoeis, flat, from plax, plak-, flat land, surface.]

placental pla·cen'tal adj.

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Britannica Concise Encyclopedia: placenta
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Organ in most mammals that develops in the uterus along with a fetus to mediate metabolic exchange. The umbilical cord attaches it to the fetus at the navel. Nutrients and oxygen in the mother's blood pass across the placenta to the fetus, and metabolic wastes and carbon dioxide from the fetus cross in the other direction; the two blood supplies do not mix. Other substances (e.g., alcohol or drugs) in the mother's blood can also cross the placenta, with effects including congenital disorders and drug addiction in the newborn (see fetal alcohol syndrome); some microorganisms can cross it to infect the fetus, but so do the mother's antibodies. The placenta, weighing a pound or more at the end of pregnancy, is expelled at parturition. Some animals eat it as a source of nutrients; in some species this stimulates lactation.

For more information on placenta, visit Britannica.com.

World of the Body: placenta
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The placenta forms from both embryonic and maternal tissues, and hosts an astonishing array of hormonal, nutritional, respiratory, excretory, and immunological functions. It is expelled after the baby as the ‘afterbirth’.

When the developing, fertilized egg at the ‘blastocyst’ stage becomes implanted in the lining of the uterus, it develops ‘villi’ — fine, frond-like cellular projections from its outermost layer, the trophoblast. It is initially through these villi that nutrients are absorbed. Then, as the embryonic circulatory system develops, blood vessels grow into the villi on the implanted side of the embryo; this becomes the fetal component of the placenta. The nutritional functions of the placenta become concentrated in the intervillous space, which is bathed by the mother's blood from the spiral arteries, which are branches of the arteries to the uterus. The spiral arteries are converted in early to mid pregnancy, by trophoblast (placental) cell invasion, to become blood vessels that more resemble veins than arteries. (If this process does not occur, then the pregnancy may become complicated by pre-eclampsia, a condition characterized by high blood pressure and protein in the urine.) Normal, converted spiral arteries ensure steady supply of blood in a low-resistance circulation. Glucose and amino acids in the mother's blood pass to capillary blood vessels in the fetal villi that dangle in the intervillous space, covered only by a thin membrane, and from them pass to the fetus, through the umbilical vein in the umbilical cord, to be used as building blocks for intrauterine growth.

The placenta. The fetal (umbilical) arteries and their branches are shown white, and the vein and its branches black
The placenta. The fetal (umbilical) arteries and their branches are shown white, and the vein and its branches black



At this same interface between mother and fetus, gas exchange occurs, with passage of oxygen to the fetus, and carbon dioxide to the mother. Thus, the placenta fulfils in intrauterine life the functions of the lungs after birth. A low concentration of oxygen in fetal blood encourages this direction of transfer, together with the particular nature of fetal haemoglobin.

Similarly, the placenta has equivalent functions to the kidney after birth in permitting the excretion of the biochemical waste products of metabolism. There are fetuses that develop without kidneys (a condition known as renal agenesis). Because of the function of the placenta they often survive until birth, although they cannot survive long thereafter.

Although one might expect the placenta to be rejected by the mother's immune system, because the fetal component is ‘foreign’, this does not happen, because of the presence of unique antigens on the cell surfaces.

In addition to these functions of exchange between the two individual blood streams, the placenta also produces an extensive array of hormones. These include human chorionic gonadotropin (HCG) produced by embryonic tissue right from the time of implantation: this promptly protects the embryo from rejection, by acting on the ovaries, causing them to sustain the hormone production that supports pregnancy. The presence of HCG also acts as the basis of pregnancy testing. After the third month, hormone production by the placenta takes over the pregnancy-supporting role from the ovary, by virtue of progressively increasing secretion of oestrogens and progesterone.

Growth of the fetus may be impaired if the placenta malfunctions. If the degree is severe, oxygenation may also become impaired, ultimately with death of the fetus and stillbirth. Other clinical problems associated with the placenta are placenta praevia, in which the placenta is located below the fetus, and placental abruption, in which the placenta separates prematurely from the wall of the uterus. Both of these conditions may be associated with brisk haemorrhage.

The placenta is ejected during the third stage of labour.

— Jim Neilson

See also antenatal development; labour; ovary; uterus; sex hormones.

Dental Dictionary: placenta
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n

The organ of metabolic interchange between the fetus and the mother.

English Folklore: placenta
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The information on popular childbirth practices is too inadequate to allow us to judge whether the placenta was always formally disposed of (not just thrown away), but this seems likely. In 20th-century midwifery, the official rule was to burn it—on the fire in the living-room or bedroom for home deliveries, in an incinerator at hospital. Some said one could tell how many more children the woman would have by counting the pops it made while burning; Aubrey said midwives predicted how long a baby would live by burning the afterbirth (Aubrey, 1686/1880: 73).

Nowadays, women who give birth at home sometimes choose to have the placenta buried in the garden, with a shrub planted over it. This is a revival of an older custom, with continental parallels (Gélis, 1991: 167-71); some informants recall the practice from before the Second World War, and add that a placenta was the best possible fertilizer for rose bushes [JS]. Others eat the placenta as a natural medicine to avoid post-natal depression, and this too may have a traditional basis, since French evidence suggests that it was sometimes eaten to encourage lactation (Gélis, 1991: 167-71). The National Childbirth Trust recently published a book, Placenta Special: Eat It or Plant It?, since it is ‘a frequent topic among young mothers’ (Independent (27 Nov. 1998), 3). A placenta can also serve as a dressing to promote healing of pressure sores and deep ulcers, and be rubbed on the mother's breasts to prevent chapping when breast-feeding [JS].

In 19th-century Cheshire, some men believed they ‘could gain the affections of a woman almost against her will by burying a placenta at the threshold of her house. This was actually done within living memory at Gatley (Cheshire) by a man named Gatley, he having procured one for two guineas. The charm failed in this instance, the woman being very self-willed’ (Moss, 1898: 169).

Some farmers disposed of a cow's or mare's placenta by hanging it in a hawthorn tree. In Hampshire in the 1930s this was done ‘as a preventative of fever in the cow’ (Vickery, 1995: 170); on a farm in Bilsdale (Yorkshire) it is still being done, to bring luck to newborn foals (FLS News 28 (1998)). They may also have wanted to thwart the animal's instinct to eat her afterbirth if (as in France) they feared she would then eat her offspring too (Gélis, 1991: 166).

 
Columbia Encyclopedia: placenta
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placenta (pləsĕn'tə) or afterbirth, organ that develops in the uterus during pregnancy. It is a unique characteristic of the higher (or placental) mammals. In humans it is a thick mass, about 7 in. (18 cm) in diameter, liberally supplied with blood vessels. The placenta is attached to the uterus, and the fetus is connected to the placenta by the umbilical cord. The placenta draws nourishment and oxygen, which it supplies to the fetus, from the maternal circulation. In turn, the placenta receives the wastes of fetal metabolism and discharges them into the maternal circulation for disposal. It also acts as an endocrine gland, producing estrogen, progesterone, and gonadotrophin. Shortly after delivery of the fetus the placenta is forced out by contractions of the uterus. Severe hemorrhage may occur if the placenta does not emerge in its entirety or if the uterus fails to contract properly.

Health Dictionary: placenta
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(pluh-sen-tuh)

An organ that forms in the uterus after the implantation of a zygote. The placenta moves nourishment from the mother's blood to the embryo or fetus; it also sends the embryo or fetus's waste products into the mother's blood to be disposed of by the mother's excretory system. The embryo or fetus is attached to the placenta by the umbilical cord. After birth, the placenta separates from the uterus and is pushed out of the mother's body.

Veterinary Dictionary: placenta
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Pl. placentae, placentas [L.] an organ characteristic of true mammals during pregnancy, joining mother and offspring, providing endocrine secretion and selective exchange of soluble bloodborne substances through apposition of uterine and trophoblastic vascularized parts. Called also afterbirth. See also fetal membranes, placentation.
Domestic animals have a chorioallantoic placenta in which the outer layer of the allantois is fused with the chorion and the fetal umbilical vessels are distributed in the connective tissue between the two. Placentae are classified in several ways; based on the tissues of the dam and the fetus that contact each other; based on the proportion of the surface area of the fetal membranes that is in fact placentacious; based on loss of tissue at birth, etc. Thus the bovine placenta is epitheliochorial, cotyledonary and nondeciduate.
The major function of the placenta is to allow diffusion of nutrients from the dam's blood into the fetus's blood and diffusion of waste products from the fetus back to the dam. This two-way exchange takes place across the placental membrane, which is semipermeable. The placenta also produces hormones such as progesterone and estrogen.

  • choriovitelline p. — a placentation in which the yolk sac becomes involved in the fetal–maternal union.
  • cotyledonary p. — distribution of the villi on the fetal chorion is localized in multiple circumscribed areas—the cotyledons.
    Cotyledonary placenta of ruminants. By permission from Sack W, Wensing CJG, Dyce KM, Textbook of Veterinary Anatomy, Saunders, 2002
  • diffuse p. — the villi on the fetal chorion is diffuse over the entire placenta as in mares and sows.
  • discoid p. — a placenta in which the chorionic villi are arranged in a circular plate as in human and rodent placentae.
  • endotheliochorial p. — the maternal vessels in the endometrium are bared to their endothelium and these are in contact with the chorion of the fetal membranes. This occurs in the bitch and queen.
  • epitheliochorial p. — the uterine epithelium of the uterus and the chorion are in contact in this placentation, and there is no erosion of the epithelium. Characteristic of cows, sows and mares. Called also adeciduate placenta.
  • hemochorial p. — a type of placenta in which all maternal layers are lost so that fetal tissue is in contact with frank maternal blood, as occurs in insectivores, rodents, rabbits and most primates.
  • nondeciduate p. — no maternal tissue is lost when the pregnancy terminates.
  • retained p. — the placenta has not been passed within 12 hours after the fetus has been delivered. Represents a potential beginning for metritis and infertility. Often difficult to assess in carnivores which rapidly eat the placenta.
  • syndesmochorial p. — a type of placentation characterized by an endometrial attachment to the chorion with a limited amount of destruction of the endometrial epithelium. Formerly thought to be characteristic of the ewe and goat doe, these species are now known to have epitheliochorial placentae.
  • zonary p. — a placenta in which the chorionic villi are restricted to an equatorial girdle, as in the bitch and queen.
Wikipedia: Placenta
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For the ancient Roman bread, see placenta (food).
For the placenta of fruit, see placentation.
Placenta
Placenta.jpg
Placenta
Precursor decidua basalis, chorion frondosum

The placenta is an organ unique to mammals that connects the developing fetus to the uterine wall. The placenta supplies the fetus with oxygen and food, and allows fetal waste to be disposed via the maternal kidneys. The word placenta comes from the Latin for cake, from Greek plakóenta/plakoúnta, accusative of plakóeis/plakoús – πλακόεις, πλακούς, "flat, slab-like",[1] in reference to its round, flat appearance in humans. Protherial (egg-laying) and metatherial (marsupial) mammals produce a choriovitelline placenta that, while connected to the uterine wall, provides nutrients mainly derived from the egg sac. The placenta develops from the same sperm and egg cells that form the fetus, and functions as a fetomaternal organ with two components, the fetal part (Chorion frondosum), and the maternal part (Decidua basalis).

Contents

Structure

In humans, the placenta averages 22 cm (9 inch) in length and 2–2.5 cm (0.8–1 inch) in thickness (greatest thickness at the center and become thinner peripherally). It typically weighs approximately 500 grams (1 lb). It has a dark reddish-blue or maroon color. It connects to the fetus by an umbilical cord of approximately 55–60 cm (22–24 inch) in length that contains two arteries and one vein.[2] The umbilical cord inserts into the chorionic plate (has an eccentiric attachment). Vessels branch out over the surface of the placenta and further divide to form a network covered by a thin layer of cells. This results in the formation of villous tree structures. On the maternal side, these villous tree structures are grouped into lobules called cotyledons. In humans the placenta usually has a disc shape but different mammalian species have widely varying shapes.[3]

Development

The placenta begins to develop upon implantation of the blastocyst into the maternal endometrium. The outer layer of the blastocyst becomes the trophoblast which forms the outer layer of the placenta. This outer layer is divided into two further layers: the underlying cytotrophoblast layer and the overlying syncytiotrophoblast layer. The syncytiotrophoblast is a multinucleate continuous cell layer which covers the surface of the placenta. It forms as a result of differentiation and fusion of the underlying cytotrophoblast cells, a process which continues throughout placental development. The syncytiotrophoblast (otherwise known as syncytium), thereby contributes to the barrier function of the placenta.

The placenta grows throughout pregnancy. Development of the maternal blood supply to the placenta is suggested to be complete by the end of the first trimester of pregnancy (approximately 12–13 weeks).

Placental circulation

Maternal placental circulation

In preparation for implantation, the uterine endometrium undergoes 'decidualisation'. Spiral arteries in the decidua are remodelled so that they become less convoluted and their diameter is increased. This increases maternal blood flow to the placenta and also decreases resistance so that shear stress is reduced. The relatively high pressure as the maternal blood enters the intervillous space through these spiral arteries bathes the villi in blood. An exchange of gases takes place. As the pressure decreases, the deoxygenated blood flows back through the endometrial veins.

Maternal blood flow is approx 600–700 ml/min at term.

Fetoplacental circulation

Deoxygenated fetal blood passes through umbilical arteries to the placenta. At the junction of umbilical cord and placenta, the umbilical arteries branch radially to form chorionic arteries. Chorionic arteries also branch before they enter into the villi. In the villi, they form an extensive arteriocapillary venous system, bringing the fetal blood extremely close to the maternal blood; but no intermingling of fetal and maternal blood occurs ("placental barrier"[4]).

Functions

Nutrition

The perfusion of the intervillous spaces of the placenta with maternal blood allows the transfer of nutrients and oxygen from the mother to the fetus and the transfer of waste products and carbon dioxide back from the fetus to the mother. Nutrient transfer to the fetus is both actively and passively mediated by proteins called nutrient transporters that are expressed within placental cells.

Adverse pregnancy situations, such as those involving maternal diabetes or obesity, can increase or decrease levels of nutrient transporters in the placenta resulting in overgrowth or restricted growth of the fetus.

Metabolic and endocrine activity

In addition to the transfer of gases and nutrients, the placenta also has metabolic and endocrine activity. It produces, among other hormones, progesterone, which is important in maintaining the pregnancy; somatomammotropin (also known as placental lactogen), which acts to increase the amount of glucose and lipids in the maternal blood; estrogen; relaxin, and beta human chorionic gonadotrophin (beta-hCG). This results in increased transfer of these nutrients to the fetus and is also the main cause of the increased blood sugar levels seen in pregnancy. This hormone (beta-hCG) ensures that progesterone and oestrogen are secreted; progesterone and oestrogen thicken and maintain the uterine lining as well as inhibit the production and release of more eggs. However after about 2 months the placenta takes on the role of producing progesterone and therefore beta-hCG is no longer needed. Beta-hCG is excreted in urine and this is what pregnancy tests detect. It also produces insulin-like growth factors (IGFs).

Cloaking from immune system of mother

Further information: Immune tolerance in pregnancy

The placenta and fetus may be regarded as a foreign allograft inside the mother, and thus must evade from attack by the mother's immune system.

For this purpose, the placenta uses several mechanisms:

However, the placental barrier is not the sole means to evade the immune system, as foreign fetal cells also persist in the maternal circulation, on the other side of the placental barrier.[7]

Birth

When the fetus is born, its placenta begins a physiological separation for spontaneous expulsion afterwards (and for this reason is also called the afterbirth). In humans, the umbilical cord is routinely clamped and severed prior to the delivery of the placenta, often within seconds or minutes of birth, a medical protocol known as 'active management of third stage' which has been called into question by advocates of natural birth and 'passive management of third stage'[8] The site of the former umbilical cord attachment in the center of the front of the abdomen is known as the umbilicus, navel, or belly-button.

Modern obstetric practice has decreased maternal death rates enormously. The addition of active management of the third stage of labor is a major contributor towards this. It involves giving oxytocin via IM injection, followed by cord traction to assist in delivering the placenta. Premature cord traction can pull the placenta before it has naturally detached from the uterine wall, resulting in hemorrhage. The BMJ summarized the Cochrane group metanalysis (2000) of the benefits of active third stage as follows:

"One systematic review found that active management of the third stage of labour, consisting of controlled cord traction, early cord clamping plus drainage, and a prophylactic oxytocic agent, reduced postpartum haemorrhage of 500 or 1000 mL or greater and related morbidities including mean blood loss, postpartum haemoglobin less than 9 g/dL, blood transfusion, need for supplemental iron postpartum, and length of third stage of labour. Although active management increased adverse effects such as nausea, vomiting, and headache, one RCT identified by the review found that women were less likely to be dissatisfied when their third stage of labour was actively managed."[1]

Risks of retained placenta include hemorrhage and infection. If the placenta fails to deliver in 30 minutes in a hospital environment, manual extraction may be required if heavy ongoing bleeding occurs, and very rarely a curettage is necessary to ensure that no remnants of the placenta remain (in rare conditions with very adherent placenta (placenta accreta)). However, in birth centers and attended home birth environments, it is common for licensed care providers to wait for the placenta's birth up to 2 hours in some instances.

Non-humans

Wiki letter w.svg
 Please help improve this article by expanding it. Further information might be found on the talk page. (April 2008)

In most mammalian species, the mother bites through the cord and consumes the placenta, primarily for the benefit of prostaglandin on the uterus after birth. This is known as placentophagy. However, it has been observed in zoology that chimpanzees, with which humans share 94%-99% of genetic material,[9][10] apply themselves to nurturing their offspring, and keep the fetus, cord, and placenta intact until the cord dries and detaches the next day.

Top: Human placenta shown a few minutes after birth. The side shown faces the baby with the umbilical cord top right. The white fringe surrounding the bottom is the remnants of the amniotic sac. Bottom: A different placenta displays side that connects to the uterine wall.

The placenta exists in most mammals and some reptiles. It is probably polyphyletic.

Pathology

Micrograph of a cytomegalovirus (CMV) infection of the placenta (CMV placentitis). The characteristic large nucleus of a CMV infected cell is seen off-centre at the bottom-right of the image. H&E stain.

Numerous pathologies can affect the placenta.

When the placenta implants too deeply:

Infections involving the placenta:

Use in medicine

Human placenta is increasingly being used in western medicine with even a branch called "placenta pharmacology" being updated regularly.[11] It has been proven to be effective in treating sores and making tissues soft and heal better.

Cultural practices and beliefs

The placenta often plays an important role in various human cultures, with many societies conducting rituals regarding its disposal. In the Western world, the placenta is most often incinerated.[12]

Some cultures bury the placenta for various reasons. The Māori of New Zealand traditionally bury the placenta from a newborn child to emphasize the relationship between humans and the earth.[13] Similarly, the Navajo bury the placenta and umbilical cord at a specially chosen site,[14] particularly if the baby dies during birth.[15] In Cambodia and Costa Rica, burial of the placenta is believed to protect and ensure the health of the baby and the mother.[16] If a mother dies in childbirth, the Aymara of Bolivia bury the placenta in a secret place so that the mother's spirit will not return to claim her baby's life.[17]

An ad in Hong Kong markets beauty products made with human placenta.

The placenta is believed by some communities to have power over the lives of the baby or its parents. The Kwakiutl of British Columbia bury girls' placentas to give the girl skill in digging clams, and expose boys' placentas to ravens to encourage future prophetic visions. In Turkey, the proper disposal of the placenta and umbilical cord is believed to promote devoutness in the child later in life. In Ukraine, Transylvania, and Japan, interaction with a disposed placenta is thought to influence the parents' future fertility.

Several cultures believe the placenta to be or have been alive, often a relative of the baby. Nepalese think of the placenta as a friend of the baby's; Malaysian Orang Asli regard it as the baby's older sibling. The Ibo of Nigeria consider the placenta the deceased twin of the baby, and conduct full funeral rites for it.[16] Native Hawaiians believe that the placenta is a part of the baby, and traditionally plant it with a tree which can then grow alongside the child.[12]

In some cultures, the placenta is eaten, a practice known as placentophagy. In some eastern cultures, such as China and Hong Kong, the placenta is thought to be healthful and is used in medicine and various health products.[18]

Additional images

Fetus of about 8 weeks, enclosed in the amnion. Magnified a little over two diameters.

Picture of freshly delivered placenta and umbilical cord wrapped around Kelly clamps

Fresh human placenta

Micrograph of a placental infection (CMV placentitis).

Micrograph of CMV placentitis.

See also

Notes

  1. ^ Henry George Liddell, Robert Scott, "A Greek-English Lexicon", at Perseus
  2. ^ Examination of the placenta
  3. ^ http://www.vivo.colostate.edu/hbooks/pathphys/reprod/placenta/structure.html Placental Structure and Classification
  4. ^ Placental blood circulation
  5. ^ "Placenta 'fools body's defences'". BBC News. 2007-11-10. http://news.bbc.co.uk/1/hi/health/7081298.stm. 
  6. ^ Clark DA, Chaput A, Tutton D (March 1986). "Active suppression of host-vs-graft reaction in pregnant mice. VII. Spontaneous abortion of allogeneic CBA/J x DBA/2 fetuses in the uterus of CBA/J mice correlates with deficient non-T suppressor cell activity". J. Immunol. 136 (5): 1668–75. PMID 2936806. http://www.jimmunol.org/cgi/pmidlookup?view=long&pmid=2936806. 
  7. ^ Williams Z, Zepf D, Longtine J, et al. (March 2008). "Foreign fetal cells persist in the maternal circulation". Fertil. Steril.. doi:10.1016/j.fertnstert.2008.02.008. PMID 18384774. 
  8. ^ http:www.sarahjbuckley.com/articles/leaving-well-alone.htm
  9. ^ Mary-Claire King, Protein polymorphisms in chimpanzee and human evolution, Doctoral dissertation, University of California, Berkeley (1973).
  10. ^ "Humans and Chimps: Close But Not That Close". Scientific American. 2006-12-19. http://www.sciam.com/article.cfm?chanID=sa003&articleID=9D0DAC2B-E7F2-99DF-3AA795436FEF8039. Retrieved 2006-12-20. 
  11. ^ http://www.amazon.com/Placental-Pharmacology-Toxicology-Rama-Sastry/dp/0849378117
  12. ^ a b "Why eat a placenta?". BBC. 2006-04-18. http://news.bbc.co.uk/1/hi/magazine/4918290.stm. Retrieved 2008-01-08. 
  13. ^ Metge, Joan. 2005. "Working in/Playing with three languages: English, Te Reo Maori, and Maori Bod Language." In Sites N.S vol. 2, No 2:83-90.
  14. ^ Francisco, Edna (2004-12-03). "Bridging the Cultural Divide in Medicine". Minority Scientists Network. http://sciencecareers.sciencemag.org/career_development/previous_issues/articles/3360/bridging_the_cultural_divide_in_medicine/. Retrieved 2008-01-07. 
  15. ^ Shepardson, Mary (1978). "Changes in Navajo Mortuary Practices and Beliefs". American Indian Quarterly. University of Nebraska Press. http://www.jstor.org/view/0095182x/ap040015/04a00080/0. Retrieved 2008-01-07. 
  16. ^ a b Buckley, Sarah J.. "Placenta Rituals and Folklore from around the World". Mothering. http://www.mothering.com/articles/pregnancy_birth/birth_preparation/amazing_placenta_side.html. Retrieved 2008-01-07. 
  17. ^ Davenport, Ann (June 2005). "The Love Offer". Johns Hopkins Magazine. http://www.jhu.edu/~jhumag/0605web/ruminate.html. Retrieved 2008-01-07. 
  18. ^ Falcao, Ronnie. "Medicinal Uses of the Placenta". http://www.gentlebirth.org/archives/eatplcnt.html. Retrieved 2008-11-25. 

References

External links

Search Wikimedia Commons Wikimedia Commons has media related to: Placenta
  • Additional Human placenta photography [2]
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Translations: Placenta
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Dansk (Danish)
n. - moderkage

Nederlands (Dutch)
moederkoek, zaadkoek (planten)

Français (French)
n. - placenta

Deutsch (German)
n. - Plazenta, Mutterkuchen

Ελληνική (Greek)
n. - (φυσιολ.) πλακούντας, ύστερο(ν)

Italiano (Italian)
placenta

Português (Portuguese)
n. - placenta (f)

Русский (Russian)
плацента

Español (Spanish)
n. - placenta

Svenska (Swedish)
n. - moderkaka, placenta

中文（简体）(Chinese (Simplified))
胎盘, 胎座

中文（繁體）(Chinese (Traditional))
n. - 胎盤, 胎座

한국어 (Korean)
n. - 태반

日本語 (Japanese)
n. - 胎盤

العربيه (Arabic)
‏(الاسم) المشيمه, السخد, غشاء الجنين الذي يخرج معه عند الولادة, جزء من سطح المبيض‏

עברית (Hebrew)
n. - ‮שלייה‬

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