Placenta Encapsulation II: Why Would I Do That?

This is the second post of this Science Friday series which explores placentophagia- the act of eating the placenta after birth. While this can take several forms for humans, one of the most common is through placenta encapsulation. This post analyzes several theories that have been proposed as the cause of placentophagia.  Check out the first post here.

   The previous post discussed some of the theories that are used to explain placentophagia.  I am not very convinced by any of those theories. However, I find the evolutionary and physiological reasons very impressive, and they actually convinced me to have placenta encapsulation done following labor and delivery.  

     The evolutionary and physiological reasons for placentophagia are primarily observed through maternal behavior.  Some observations, while relatively weak, indicate an increased attachment behavior between mother and infant.  Much stronger evidence supports the positive effects that placentophagia has on lactation, presumably because the placenta’s high estrogen and lactogen content.  As an avid proponent of breastfeeding, I find this finding one of the most compelling arguments for placentophagia.  Mothers currently face countless obstacles to breastfeeding; consequently, I find any method of easing a new mom’s breastfeeding journey is immeasurably important! 

        Another evolutionary effect, although one that may not yet be possible in humans, is the placenta’s impact on the maternal immune system.  Because the fetus and fetal placenta contain aspects of both the mother and the father, a mother’s immune system could reject some antigens found in the fetus’s blood.  In humans, this is observed when an Rh negative mother is carrying an Rh positive fetus.  During her first pregnancy, she creates antibodies to fight this seemingly invading species.  These antibodies could potentially harm future Rh positive fetuses.  Humans receive can receive a Rhogam shot to counteract this reaction.  In other mammals, however, placentophagia may serve to block the creation of the antibodies.  In this way, nature has provided a way to ensure the survival of mama and babies.  As someone who requires a Rhogam shot (I just had my third a few days ago!) and who hates shots, I’m hoping for more research on this topic for human use!

Source:
Kristal, M.B. (1980). Placentophagia: A biobehavioral enigma. Neuroscience and Biohehavioral Reviews, (4)141-150.