thumb|Placental morphologies of varying placental mammals
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. Parturition involves the delivery of the neonate, as well as the placenta and fetal membranes. 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.
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.
In rabbits
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. 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.
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. 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.
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.
Those who advocate placentophagy in humans believe that eating the placenta prevents postpartum depression and other pregnancy complications. 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." While no scientific study has proven any benefits, a survey was conducted by American 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".
Human placenta has also been an ingredient in some traditional Chinese medicines, including using dried human placenta, known as ziheche (), to treat wasting diseases, infertility, impotence and other conditions.
Most recently, the CDC 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 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.
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