Eating the placenta after birth offers no benefit to new mothers, a new study suggests.

Research in Nevada found the increasingly common practice of consuming capsules made from the organ in the weeks following birth did almost nothing to improve maternal fatigue or ward off depression.

The work did show that ingesting placenta capsules produced small but detectable changes in hormone concentrations, but it is not known whether this has any beneficial effect.

Advocates of the practice point to widespread maternal placentophagy - eating the placenta - in the animal kingdom, however official bodies such as the Royal College of Midwives do not recommend it, saying their is no evidence of any benefit.

The new study involved 12 women who took placenta capsules and 15 who took placebo pills in the weeks after giving birth.

Researchers tested the efficacy of placenta capsules in promoting various health benefits, including stemming the onset of postpartum 'baby blues' and depression of new mothers.

The results of the study, published in the online journal Women and Birth, found that such claims are not clearly supported.

However the work did show that ingesting placenta capsules produced small but detectable changes in hormone concentrations that show up in a mother's circulating hormone levels.