Placentophagy

Placentophagy (from 'placenta' + Greek φαγειν, to eat) is the act of mammals eating the placenta of their young after childbirth.

The placenta contains high levels of prostaglandin which stimulates involution (an inward curvature or penetration, or, a shrinking or return to a former size) of the uterus, in effect cleaning the uterus out. The placenta also contains small amounts of oxytocin which eases birth stress and causes the smooth muscles around the mammary cells to contract and eject milk.

There is also a school of thought that holds that placentophagy naturally occurred to hide any trace of childbirth from predators in the wild, though the fact that amniotic fluid is not similarly ingested by the mother seems to discredit this theory. Most placental mammals participate in placentophagy, including, surprisingly, herbivorous ones. Pinnipedia and Cetacea are exceptions to mammalian placentophagy, as is the camel. Placentophagy has been observed in Insectivora, Rodentia, Chiroptera, Lagomorpha, Carnivora, Perissodactyla, Artiodactyla (with the camel as a noted exception), and Primates. Marsupials, which are an order of metatherian (pouched) mammals, resorb rather than deliver the placenta, and therefore cannot engage in placentophagia; they do, however, vigorously lick birth fluids as they are excreted.^[1]

According to preliminary research performed several decades ago, ingestion of placenta can enhance opioid-mediated analgesia in pregnant rats, but only under very specific conditions. Rats only experienced increased analgesia if they received footshock or morphine and only responded if they ingested a small amounts of placenta. Ingesting large amounts of placenta did not significantly affect pain sensation. There have been no scientific studies which show that placentophagy enhances analgesia in humans. ^[2]

Human placentophagy

Although the placenta is revered in many cultures, very few customarily eat the placenta after the newborn's birth. Those who advocate placentophagy in humans believe that eating the placenta prevents postpartum depression and other pregnancy complications^[3]. 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."^[4] Human placenta has also been an ingredient in some traditional Chinese medicines,^[5] including using dried human placenta, known as "Ziheche" (simplified Chinese: 紫河车; traditional Chinese: 紫河車; pinyin: Zǐhéchē), to treat wasting diseases, infertility, impotence and other conditions.^[6]

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