While its benefits have been heralded for hundreds of years, the act of consuming the placenta — the specialized organ that nourishes the fetus through the umbilical cord — has become popular again thanks to blogs, the media and celebrities discussing the practice. Purported benefits include a surge of nutrients and vitamins, an increase in breast milk production, and a decrease in postpartum depression symptoms and pain.

This renewed interest has led researchers to take a closer look at placentophagy. The latest study, actually a review of 10 previous studies, comes to us from Northwestern University, which found little evidence either for or against the practice. 

"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," lead study author Cynthia Coyle, a clinical psychologist at Northwestern University, told the BBC

Researchers are concerned that because there are no standards for eating the placenta, women may put themselves at risk or negate any of the perceived benefits through improper preparation. For instance, one study reviewed found that rats that ate their placentas immediately after birth (a common practice in the animal kingdom) had less pain. However, because the placenta is sensitive to temperature, these pain alleviating benefits last no longer than 24 hours. In most human cases, the placenta is not eaten immediately — or could be improperly preserved via cooling or dehydrated tablets, potentially limiting its impact. 

"There are no regulations as to how the placenta is stored and prepared, and the dosing is inconsistent," added Coyle. "Women really don't know what they are ingesting." 

The other risk the researchers point out relates to the placenta's function as a filter of toxins between the mother and child. It's currently unclear whether any toxins stored in the organ might be harmful if consumed. 

"We have to remember that the placenta is there to nourish the baby during pregnancy and filter toxins so the baby isn't exposed to substances it shouldn't be," Dr. Jill Rabin, co-chief of the division of ambulatory care at Women's Health Programs in Hyde Park, New York, told WebMD. "The risks of eating it are probably small, but we simply don't know."

The unknowns regarding the pros and cons mean that placentophagy is a field ripe for study. A 2013 study of 189 women who had eaten their placentas found that a majority had reported benefits from the act and would do it again. 

"Further research is necessary to determine if the described benefits extend beyond those of placebo effects, or are skewed by the nature of the studied sample," the study concluded. 

As for women interested in eating their placentas, doctors aren't necessarily discouraging the practice.

"I just inform them that it might not do anything, but it's definitely her choice," Dr. Crystal Clark, who co-authored the Northwestern article, told CNN. "I would not recommend at this time that a woman forgoes iron capsules or antidepressants or other treatments for which there is evidence of benefit."

Related on MNN: 

Michael d'Estries ( @michaeldestries ) covers science, technology, art, and the beautiful, unusual corners of our incredible world.

Eating the placenta carries no obvious health benefits, study finds
Researchers at Northwestern review 10 studies and find 'no good data' for or against the trendy practice.