Eating the placenta after childbirth has become a longstanding tradition in many cultures across the world, including the United States. However, researchers at Northwestern University have found that the common practice does not have any health benefits, and may even have unknown risks.

The placenta is an organ that keeps the unborn baby's blood supply separate from the mother's, and is linked to the baby by the umbilical cord. Oxygen and waste nutrients flow from the mother's blood supply to the unborn baby's and waste products pass from the baby through the placenta to the mother's blood stream.

Many women who eat the placenta, often eating it raw, cooked or encapsulated, believe that the practice offers protection against postpartum depression, reduces post-delivery pain, boosts energy, aids lactation, promotes skin elasticity, enhances maternal bonding, or replenishes iron in the body.

The study, published in Archives of Women's Mental Health, reviewed 10 current published research studies on placentophagy. Researchers found there are no benefits that can be proven and the risks to both mother and child if the placenta is eaten, is largely unknown.

"Our sense is that women choosing placentophagy, who may otherwise be very careful about what they are putting into their bodies during pregnancy and nursing, are willing to ingest something without evidence of its benefits and, more importantly, of its potential risks to themselves and their nursing infants," says lead author Cynthia Coyle, a Northwestern University Feinberg School of Medicine faculty member and a psychologist.

Currently, placenta storage and preparation is not regulated and the dosage is inconsistent, researchers said. The study authors also noted that more research is necessary to understand exactly what is in the placenta.

In recent years, the practice of eating the placenta has increased in popularity with many celebrities talking about the benefits. However, this increase in popularity could mean that more mothers and even infants are put at greater risk since currently physicians have no idea what is in the placenta and how safe it is to consume, especially if eaten raw.

"Our sense is that people aren't making this decision based on science or talking with physicians. Some women are making this based on media reports, blogs and websites," says coauthor Dr. Crystal Clark, an assistant professor of psychiatry and behavioral sciences at Northwestern.