Eating a baby's placenta after birth does not stop depression or increase energy levels of new mothers, a US study has found.

But advocates in Australia have welcomed the review, saying the area needs more scientific research.

The research, published in the periodical Archives of Women's Mental Health, reviewed 10 published articles on placenta eating.

It found no data to support claims of preventing depression, reducing pain or increasing energy.

"Our sense is that women are willing to ingest something without evidence of its benefits and, more importantly, of its potential risks to themselves and their nursing infants," said the study's lead author, psychologist Cynthia Coyle from Northwestern University in Illinois.

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

But the practice needs more scientific research into its benefits, according to Samantha Birch, who prepares placentas for consumption.

"We know there's no research. We want the research, we want to know ourselves, as specialists. We want it to be safer in this country. It's a different thing in other countries. We are very lucky here for it to be a little safer. We welcome the research," she said.

Ms Birch is working on the development of a code of conduct for the procedure.

But she said she was not worried about the risks of placenta eating, despite the lack of research.

"I feel there is very minimal risk with the way that it's done. I've put a lot of time into making sure that it's food safety standard and there's no cross-contamination," she said.

How a placenta is prepared for eating

As part of her job Ms Birch prepares placentas for consumption.

The most common method is placenta encapsulation, where the placenta is cleaned, either steamed or cut up very thinly, and then dehydrated and put into capsules.

Women can consume the placenta in capsule form. ( ABC: Jon Coghill )

However, Ms Birch said it was better to digest the placenta fresh after birth.

"It's just cleaned and a walnut size piece put into a smoothie with water and organic banana and berries of the mother's choice," she said.

"Otherwise they can have raw pieces that go under the tongue for quick absorption."

Ms Birch has never eaten placenta herself, but says feedback from her clients about the health benefits has been consistently positive.

In some cases, clients reported not needing blood transfusions after taking the pills.

Mum says energy levels increased after taking placenta pills

Mother-of-two Victoria Drennan has eaten her own placenta and is convinced of the health benefits.

She ate her placenta in a tablet form after the birth of her second child, believing it would boost her energy levels and prevent depression.

Her father had died and her husband was working away from home.

"I didn't expect to have the energy that I did have, so I do put that down to the pills," she said.

"I believe that I severely avoided the baby blues. My energy levels 100 per cent increased, and also my milk production increased from the previous child."

Scientific evidence or not, the practice is becoming more popular, especially since celebrities such as Kourtney Kardashian shared her experience of eating her placenta on Instagram.

Ms Drennan said although some people found the thought of eating placenta off putting, it should not be dismissed.

"A lot of people find it really gross, the thought of it, but I think when you get over the thought of what you're actually doing, you know ... you can't taste anything, just see how you go," she said.