Taking fish oil capsules during pregnancy does not provide any additional benefits, Australian researchers have said.
International recommendations currently claim that taking fish oil, which is high in omega 3 fatty acids, when pregnant helps babies' cognitive development.
However, a new report published in the Journal of the American Medical Association suggests that there is no evidence for this.
It adds that women who take such capsules do not have a reduced risk of post-natal depression.
"Despite the paucity of hard evidence, women are being recommended to increase their intake of fish oil fats in pregnancy and the nutritional supplement industry is successfully marketing products with fish oil, claiming they optimise brain function in both mother and infant," commented lead researcher Dr Maria Makrides of the University of Adelaide.
She added: "Before omega 3 supplementation in pregnancy becomes widespread, it is important to establish not only any benefits, but also any risks to mother or child."