Editing Placentophagy

{{Short description|Act of mammals eating the placenta of their young after childbirth}}
{{Use dmy dates|date=June 2021}}
[[File:Placental morphologies encountered in placental mammals.jpg|thumb|Placental morphologies of varying placental mammals]]
[[File:Goat_eating_placenta.jpg|alt=|thumb|Mother goat engaging in placentophagy]]
'''Placentophagy''', also known as placentophagia, is the act of consuming part or all of the [[afterbirth]] following parturition in mammals.<ref name=":12">{{Cite journal|last=Hayes|first=Emily Hart|date=1 January 2016|title=Consumption of the Placenta in the Postpartum Period|url=https://www.jognn.org/article/S0884-2175(15)00009-X/abstract|journal=Journal of Obstetric, Gynecologic & Neonatal Nursing|language=en|volume=45|issue=1|pages=78–89|doi=10.1016/j.jogn.2015.10.008|issn=0884-2175|pmid=26815801|access-date=29 June 2021|url-access=subscription}}</ref> Parturition involves the delivery of the neonate, as well as the placenta and fetal membranes.<ref name=":02">{{Cite journal|last=Kristal|first=Mark B.|date=1 June 1980|title=Placentophagia: A biobehavioral enigma (or De gustibus non disputandum est)|journal=Neuroscience & Biobehavioral Reviews|volume=4|issue=2|pages=141–150|doi=10.1016/0149-7634(80)90012-3|pmid=6999389|s2cid=10468943|issn=0149-7634}}</ref> The [[placenta]] is a critical organ that develops in the maternal uterus during pregnancy to support the [[fetus]]. It connects to the fetus via the umbilical cord in order to allow nutrient transport, waste excretion and gas exchange between mother and fetus.<ref name=":02" /> The morphological features of the placenta differ among species, but the function is universal.
The behaviour is characteristic to the mother of the majority of placental mammals.<ref name=":12" /> Significant documentation has been provided on placentophagy in a range of animals.

Anomalies generally include humans and aquatic species, as well as camels.<ref name=":02" /> However, the concept is becoming more popular among women in the West, despite its controversial overtone.<ref name=":12" />

Theories as to why mammals engage in placentophagy are related to the many proposed benefits of placental consumption. These vary between animals but tend to be behavioural, medical or spiritual in nature.<ref name=":02" /><ref>{{cite journal|last1=Ober|first1=William|date=1979|title=Notes on Placentophagy|journal=Bulletin of the New York Academy of Medicine|volume=55|issue=6|pages=591–599|pmid=111747|pmc=1807646}}</ref><ref name=":22">{{cite journal |last1=Kristal |first1=Mark B. |date=1991 |title=Enhancement of Opioid-Mediated Analgesia: A Solution to the Enigma of Placentophagia |journal=Neuroscience and Biobehavioral Reviews |volume=15 |issue=3 |pages=425–435 |doi=10.1016/S0149-7634(05)80035-1 |pmid=1956610 |s2cid=6331181}}</ref>

== Prevalence ==
Placentophagy is a normality in most members of the taxonomic group [[Eutheria]]. It has been observed in animals ranging from rodents to primates, and even in some instances humans. The most extensive study has been on animals in orders [[Rodentia]], [[Chiroptera]], [[Lagomorpha]], [[Carnivora]], [[Perissodactyla]], [[Artiodactyla]], and [[Primates]].<ref name=":02" /> Exceptions to the ubiquitous behaviour in mammals can be seen in humans, sea mammals and [[camelids]]. It is suggested that the portion of marine species that do not practice placentophagy are ones that deliver their offspring in the water because beneficial components are dispersed upon expulsion from the mother, and that the domestication of camelids has eradicated the behaviour by placing stress and selective pressure on the species.<ref name=":3">{{cite journal|last1=Kristal|first1=Mark|last2=DiPirro|first2=Jean|last3=Thompson|first3=Alexis|date=May 2012|title=Placentophagy in Humans and Nonhuman Mammals: Causes and Consequences|journal=Ecology of Food and Nutrition|volume=51|issue=3|pages=177–197|doi=10.1080/03670244.2012.661325|pmid=22632059|bibcode=2012EcoFN..51..177K |s2cid=540223}}</ref>

=== In rabbits ===
[[File:Oryctolagus_cuniculus_Tasmania_2.jpg|thumb|Domestic rabbit, ''Oryctolagus cuniculus,'' used as model species in study of placentophagy|alt=]]
Placentophagia in rabbits is exclusively performed by maternal figures that have recently given birth. A study shows that even when pregnant and pre-parturient female rabbits are presented with placental meal there is little participation in the behavior but all postpartum mothers ate the afterbirth. When compared with the consumption of liver, another protein source, the occurrence of placentophagia alone increases by roughly 55% in the short 1–5 day period following parturition.<ref name=":5">{{Cite journal|last1=Melo|first1=Angel I.|last2=González-Mariscal|first2=Gabriela|date=2003|title=Placentophagia in rabbits: Incidence across the reproductive cycle: Placentophagia in Rabbits|journal=Developmental Psychobiology|language=en|volume=43|issue=1|pages=37–43|doi=10.1002/dev.10118|pmid=12794777}}</ref> The liver is preferential to non-pregnant, pregnant and pre-parturient mothers consistently as opposed to post-partum mothers who chose to consume only placenta when presented with both. The same study also looked at the interest of the placenta in pregnant rabbits, they saw that in the days leading up to delivery the animals were more intrigued by the placenta when it was presented, which was shown by increasing sniffing of the placenta. The attraction was not demonstrated towards the liver. This infers that there is a tie between elements prompting both delivery and placentophagy in pregnant maternal rabbits.<ref name=":5" /> In some instances placentophagia is tied to [[cannibalism]] in rabbits. As the mother engages in the act of consuming the placenta, they accidentally ingest the neonate as well.<ref>{{Cite journal|last1=Clauss|first1=Marcus|last2=Lischke|first2=Andreas|last3=Botha|first3=Heike|last4=Hatt|first4=Jean-Michel|date=2016|title=Carcass consumption by domestic rabbits (Oryctolagus cuniculus)|journal=European Journal of Wildlife Research|language=en|volume=62|issue=1|pages=143–145|doi=10.1007/s10344-015-0980-y|s2cid=16166906|issn=1612-4642}}</ref>

=== In rats ===
Placentophagia has been studied most commonly in rodents, specifically rats. There have been multiple conclusions drawn from the available literature. One major finding is that the consumption of the afterbirth and associated materials increases the onset and intensity of maternal behavior in rats.<ref name=":22" /> The increased contact between the adult and the infant is what enhances the adoption of parental behavior. In addition to increasing the parenting tendencies of mother rats, it has been seen that placentophagia by female weanling laboratory rats when the mother births a subsequent litter, elevates [[alloparenting]] behavior toward their siblings.<ref>{{Cite journal|last1=Harding|first1=Kaitlyn M.|last2=Lonstein|first2=Joseph S.|date=2014|title=Placentophagia in weanling female laboratory rats: Placentophagia in Weanling Females|journal=Developmental Psychobiology|language=en|volume=56|issue=6|pages=1290–9|doi=10.1002/dev.21208|pmc=4119531|pmid=24604548}}</ref> Additional research has shown that ingestion of the placenta and amniotic fluid influences the pain tolerance in pregnant rats via elevation of naturally occurring opioid-mediated analgesia.<ref name=":22" /> Production of endogenous opioids produced by the central nervous system, is increased during the birthing process which raises the pain threshold of the mother. When coupled with the ingestion of placenta or amniotic fluid, there is a drastic increase in the opioid effect. A test whereby rats were given meat rather than placenta supported the contribution of the afterbirth components to the enhanced opioid effect by showing no increase in the pain threshold of the post-partum mother.<ref name=":22" /><ref name=":3" />

== Hypothesized benefits ==
There are numerous hypothesized benefits to the practice of placentophagy in both human and nonhuman mammals, which are seen as the direct motivation for various animals to engage in the consumption of the afterbirth. Many of these proposed benefits have since been disproved through scientific study.

=== Satiation of hunger ===
Some initial conjectures related directly to the satiation of specific and general maternal hunger.<ref name=":3" /> These hinged on the idea that prior to parturition mothers ceased to eat and so, immediately after birth they consumed the placenta to satisfy an intense hunger. A further idea was that of specific hunger, according to which the maternal figure participated in placentophagy in order to replenish any resources depleted during pregnancy that were contained within the placenta.<ref name=":22" /> This was later disproved by studies on rats and other species showing that a wide range of animals do not typically decrease the amount of food or water taken in prior to delivery, and that rats presented with placenta will consume it regardless of pregnancy or virginity.<ref name=":02" /><ref name=":22" /><ref name=":4">{{cite journal|last1=Kristal|first1=Mark|last2=Wampler|first2=Richard|date=1973|title=Food and water intake prior to parturition in the rat|journal=Physiological Psychology|volume=1|issue=3|pages=297–300|doi=10.3758/BF03326927|doi-access=free}}</ref>

=== Cleanliness and protection against predation ===
Another aspect of placentophagy that was initially considered a beneficial reason for its occurrence was that the consumption of the afterbirth ensured cleanliness of the nest and eliminated any sign of new and vulnerable offspring.<ref name=":02" /> It was suggested that nesting animals, who would then rear their young within the nest, benefited by having an aseptic area. Further, predators would be attracted to the site of parturition by the scent of blood and of fetal tissue, so ingesting the afterbirth would eliminate the ability for predators to easily locate newborns. This would in turn provide protection for the defenseless young.<ref name=":02" /> These hypothesized benefits were later rejected because the act of consuming the placenta would be more time-consuming than merely abandoning the site of parturition or removing the afterbirth from the nesting area, each of which would provide the same benefit as placentophagy was presumed to provide.<ref name=":02" />

=== Increased pain threshold ===
A newer hypothesis about the maternal consumption of afterbirth in mammals is that the placenta contains compounds that increase pain tolerance post parturition.<ref name=":22" /><ref name=":4" /> Although it is known that during pregnancy and labour there is a natural increase in internal production of enkephalins and endorphins that decrease the sensation of pain, studies indicated that the consumption of placenta by maternal rats after delivery spiked the subsequent numbers of these opioids.<ref name=":3" /> This was due to the active ingredient present in the placenta as well as the amniotic fluid, placental opioid-enhancing factor (POEF). It is important to note that afterbirth also contains amniotic fluid, and scientists believe its consumption may be equally as important in the elevation of pain threshold as is the placental ingestion. Amniotic fluid is likely taken in unknowingly by cleaning the genital area prior or post delivery, or by cleaning or kissing the infant soon after expulsion.<ref name=":22" /><ref name=":4" />

== Evolution ==
Placentophagy evolved independently in different lineages as adaptations to various challenges faced by ancestral species.<ref name=":3" /> The behaviour was ultimately attractive to the maternal subject based on the hypothesized benefits discussed above but provided some kind of advantage. Based on this advantage, placentophagy was selected for by natural selection which lead to its persistence in mammal species.<ref name=":3" />

== Human placentophagy ==
{{Main|Human placentophagy}}

[[File:Ziheche.jpg|thumb|left|200px|Dried human placenta as medicine (''ziheche'') (紫河车)]]
Although the placenta is revered in many cultures, there is scarce evidence that any customarily eat the placenta after the newborn's birth.<ref name=Cultural>{{cite web|author1=SM Young|author2=DC Benyshek|name-list-style=amp|url=http://www.lucina.ca/plresearch/In%20search%20of%20human%20placentophagy%202010.pdf|title=In Search of Human Placentophagy: A Cross-Cultural Survey of Human Placenta Consumption, Disposal Practices, and Cultural Beliefs|publisher=Ecol Food Nutr. 2010 Nov-Dec;49(6):467-84.|access-date=20 June 2012|archive-url=https://web.archive.org/web/20151029060400/http://www.lucina.ca/plresearch/In%20search%20of%20human%20placentophagy%202010.pdf|archive-date=29 October 2015|url-status=dead}} Abstract at [https://www.ncbi.nlm.nih.gov/pubmed/21888574 NIH website], accessed 20 June 2012</ref>

Those who advocate placentophagy in humans believe that eating the placenta prevents [[postpartum depression]] and other pregnancy complications.{{Citation needed|date=June 2019}} [[Obstetrics|Obstetrician]] and spokesperson for the [[Royal College of Obstetricians and Gynaecologists]] Maggie Blott disputes the post-natal depression theory, stating there is no medical reason to eat the placenta: "Animals eat their placenta to get nutrition – but when people are already well-nourished, there is no benefit, there is no reason to do it."<ref>{{Citation
|url=http://news.bbc.co.uk/1/hi/magazine/4918290.stm
|title=Why eat a placenta?
|work=[[BBC News]]
|access-date=12 December 2007
|date=18 April 2006}}</ref> While no [[Randomized controlled trial|scientific study]] has proven any benefits, a survey was conducted by American [[Anthropology|medical anthropologists]] at the [[University of South Florida]] and [[University of Nevada, Las Vegas]]. Among the respondents, about three-fourths claimed to have positive experiences from eating their own placenta, citing "improved mood", "increased energy", and "improved lactation".<ref>{{cite web|url=http://news.unlv.edu/article/steamed-dehydrated-or-raw-placentas-may-help-moms%E2%80%99-post-partum-health|publisher=UNLV News Center|title=Steamed, Dehydrated or Raw: Placentas May Help Moms' Post-Partum Health. UNLV anthropology survey examines why women consume their placentas after childbirth.|last=Bawany|first=Afsha|date=27 February 2013|access-date=25 March 2013}}</ref>
<ref>{{cite web|url=http://news.unlv.edu/sites/default/files/EFN%20Placentophagy%20Survey%20(Selander,%20Cantor,%20Young%20and%20Benyshek%202013).pdf|publisher=Ecology of Food and Nutrition|title=Human Maternal Placentophagy: A Survey of Self-Reported Motivations and Experiences Associated with Placenta Consumption|author1=J. Selender |author2=A. Cantor |author3=S. Young |author4=D. Benyshek |access-date=25 March 2013|url-status=dead|archive-url=https://web.archive.org/web/20150216214212/http://news.unlv.edu/sites/default/files/EFN%20Placentophagy%20Survey%20%28Selander,%20Cantor,%20Young%20and%20Benyshek%202013%29.pdf|archive-date=16 February 2015}}</ref>

Human placenta has also been an ingredient in some [[traditional Chinese medicine]]s,<ref>{{Cite web
|url=http://www.news-medical.net/print_article.asp?id=1333
|title=Traditional Chinese medicine contains human placenta
|publisher=News-Medical.Net
|date=8 May 2004
|access-date=12 December 2007}}</ref> including using dried human placenta, known as ''ziheche'' ({{zh|s=[[wikt:紫河车|紫河车]]|t=紫河車|p=Zǐhéchē}}), to treat wasting diseases, infertility, impotence and other conditions.<ref>{{Citation |author1=Tierra, Lesley |author2=Tierra, Michael |title=Chinese traditional herbal medicine |publisher=Lotus Light Pub |location=Twin Lakes, WI |year=1998 |isbn=978-0-914955-32-0 | pages = [https://books.google.com/books?id=Zm6QTqNt3JEC&pg=PT225 225] }}</ref>
Most recently, the CDC<ref>{{cite journal |journal= MMWR. Morbidity and Mortality Weekly Report|title=Notes from the Field: Late-Onset Infant Group B Streptococcus Infection Associated with Maternal Consumption of Capsules Containing Dehydrated Placenta — Oregon, 2016|volume=66 |issue=25 |pages=677–678 |doi=10.15585/mmwr.mm6625a4 |pmid=28662016 |pmc=5687501 |year=2017 |last1=Buser |first1=Genevieve L. |last2=Mató |first2=Sayonara |last3=Zhang |first3=Alexia Y. |last4=Metcalf |first4=Ben J. |last5=Beall |first5=Bernard |last6=Thomas |first6=Ann R. }}</ref> published a report of a newborn infected with group B ''Streptococcus'' (GBS) bacteria likely after the mother ingested placenta capsules. Consequently, the CDC said that placenta capsule ingestion should be avoided and to educate mothers interested in placenta encapsulation about the potential risks. A recent publication<ref>{{cite journal|last1=Farr|first1=Alex|last2=Chervenak|first2=Frank A.|last3=McCullough|first3=Laurence B.|last4=Baergen|first4=Rebecca N.|last5=Grünebaum|first5=Amos|date=28 August 2017|title=Human placentophagy: a review|url=https://www.ajog.org/article/S0002-9378(17)30963-8/pdf|journal=American Journal of Obstetrics and Gynecology|language=en|volume=218|issue=4|pages=401.e1–401.e11|doi=10.1016/j.ajog.2017.08.016|issn=0002-9378|pmid=28859955|s2cid=4450981|access-date=29 June 2021|url-access=subscription}}</ref> advised that physicians should discourage placentophagy because it is potentially harmful with no documented benefit.

British celebrity chef [[Hugh Fearnley-Whittingstall]], known for his series of River Cottage programmes, notoriously cooked and ate a human placenta on one of his programmes.<ref>{{cite web|date=28 May 1998|title=Channel 4 rapped for serving placenta|url=http://news.bbc.co.uk/1/hi/entertainment/101944.stm|publisher=BBC|access-date=29 June 2021}}</ref>

Pg.104-7 in [[Cecil Adams]]'s ''[[Return of the Straight Dope]]'' (1994) describes a home childbirth, followed by placentophagy, in [[Berkeley, California]].

==See also==
* [[Autocannibalism]]

==References==
{{Reflist|30em}}

==External links==
*{{Commons category-inline|Placentophagy}}
*{{Cookbook-inline|Placenta}}

{{Feeding}}

{{Cannibalism}}
[[Category:Placenta]]
[[Category:Animal cannibalism]]