The placenta, which supplies the developing fetus with oxygen via the umbilical cord, does not act as a filter, retaining toxins and waste. The placenta carries waste to the mother's blood supply, which is then disposed of by her kidneys and lungs. In a recent study, 17 hormones and 25% of daily iron were found in encapsulated placenta. No harmful amounts of heavy metals were present in the encapsulated placenta that was tested.
Gryder, L. K., Young, S. M., Zava, D., et al. (2017). Effects of human maternal placentophagy on maternal postpartum iron status: A randomized, double-blind, placebo controlled pilot study. Journal of Midwifery and Women’s Health 62:68-79