Editing Placentophagy (section)

== 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" />