I first learned of mother’s ingesting their placenta as a supplement after childbirth while in school for Traditional Chinese Medicine. This has been in practice in China and many cultures for thousands of years. Almost every mammal ingests their own placenta after the birth, sometimes even ignoring the young until the placenta has been completely ingested.
Traditional Chinese Medicine has used placenta for thousands of years to augment the qi (energy), nourish the blood, and augment the kidney essence. In layman’s terms, it brings the body back into balance, replenishing what was lost during childbirth. In China it is also used for debilitating chronic diseases and widely used as an anti-aging treatment, as well as a variety of other illnesses, including fatigue and insufficient lactation.
In many cultures the placenta is considered the tree of life, and indeed, without it life would not be possible.