Nature knows what’s best! Read this fascinating article on the possible evolutionary purpose for placentophagia.
There must be some other evolutionary cause for placentophagia. A very interesting adaptive theory is that consuming placenta may actually affect the mother’s immune system, by suppressing her body’s inclination to create antibodies as a response to antigens present in the baby’s blood. As an example, women who are negative for the Rh antigen can have difficulty supporting a subsequent pregnancy if her first baby is positive for the Rh antigen. Her body can create anti-Rh antibodies, which then attempt to fight off the next pregnancy if the next baby is Rh-positive, mistakenly recognizing it as a threat. Placentophagia may actually cause a suppression of this response, allowing her to have successful subsequent pregnancies. Human women who are Rh-negative are often encouraged to get a shot of Rhogam, a vaccine that blocks the creation of high levels of these antibodies. Mammals may have adapted their own antidote over thousands of generations, simply by practicing placentophagy.
This is an exciting area of research, and we will hopefully learn much more about the benefits of placentophagy in the future. Perhaps we will even discover that Nature has had a cure for this antibody issue all along.