Placentophagy, the consumption of the placenta and other afterbirth materials by a mother after birth, is a widespread behavior among most placental mammals. It occurs in over 4,000 species, ranging from rodents to non-human primates. Its prevalence suggests underlying biological and evolutionary advantages. It is almost universal among terrestrial eutherian mammals, with exceptions like marine mammals, camelids, and humans.
Physiological Benefits for the Mother
Placentophagy primarily offers nutritional replenishment to the mother. The placenta is rich in protein, iron, and minerals. Consuming these nutrients aids recovery from the energy demands of childbirth.
Beyond nutrition, the placenta contains hormones that may confer benefits. Hormones like oxytocin and prostaglandins are present. Oxytocin aids uterine contractions, helping the uterus return to its pre-pregnancy size and expelling any remaining afterbirth. Prostaglandins also contribute to uterine involution and can help manage inflammation and pain. These hormones may also support milk production, facilitating lactation.
Research also suggests pain management through Placental Opioid-Enhancing Factor (POEF). Studies in rodents indicate POEF, found in the placenta and amniotic fluid, can increase the mother’s pain threshold by enhancing natural opioids around birth. This heightened pain tolerance allows the mother to focus on newborn care.
Survival and Environmental Factors
Placentophagy plays significant roles in the survival of mother and offspring in the wild. One theory suggests consuming the placenta removes birth evidence, reducing predator attraction. The scent of blood and fetal tissues can draw predators to a vulnerable birthing site, threatening newborns and the recovering mother.
Ingesting the afterbirth keeps the birthing area clean and hygienic. This minimizes infection risk for mother and young, as decaying matter breeds bacteria. Maintaining a sanitary environment is important for species giving birth in confined spaces like dens or nests.
Placentophagy is also rooted in instinctual behavior, reflecting evolutionary pressures. It is considered an adaptation providing an overall advantage, selected for by natural selection. This drive may be linked to ancestral survival strategies, ensuring species propagation by enhancing maternal health and offspring safety.
The Human Perspective
While common among most mammals, placentophagy is not a routine practice in human cultures. Historically, ethnographic records show an absence of maternal placentophagy as a widespread cultural tradition. Instead, many human cultures dispose of the placenta through burial or other ritualistic means.
Despite its historical rarity, interest in human placentophagy has grown recently, particularly in Western industrialized societies. This modern trend often involves processing the placenta into capsules. Proponents suggest benefits such as improved mood, increased energy, enhanced milk production, and pain relief.
However, scientific consensus and robust evidence supporting these benefits are lacking. Reviews of existing studies, including those on processed placenta, find insufficient data to confirm health advantages. There are also risks, including exposure to bacteria and viruses if the placenta is not handled or processed properly. The placenta also filters toxins and pollutants during pregnancy, which could remain in the tissue.