Consumption of fish oil capsules during pregnancy does not reduce post-natal depression

A University of Adelaide study has found no evidence that taking fish oil capsules during pregnancy can help reduce the risk of post-natal depression, contrary to international recommendations.

In an article published today in the Journal of the American Medical Association, Professor Maria Makrides says a study of 2400 pregnant women in five Australian maternity hospitals between 2005 and 2009 supports this finding.

Professor Maria Makrides, who is Professor of Human Nutrition at the University of Adelaide and Deputy Director of the Women's and Children's Health Research Institute, says the results also contradict existing recommendations that fish oil capsules taken in pregnancy help newborn babies' language and cognitive development.

In a five-year study led by Professor Makrides, half the women in the latter stages of pregnancy were given fish oil capsules and the other half vegetable oil capsules. There was no significant difference in either the incidence of post-natal depression or neuro developmental outcomes of their children.

"These results show that recommendations to increase omega 3 fatty acids in pregnancy are being made without sound evidence," Professor Makrides says.

She says previous findings from the United States and Europe suggesting the benefits of fish and seafood during pregnancy were based on observational studies that could not separate the influence of social variables from the intake of fish and seafood.

"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.

"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," she says.

While depressive symptoms were more common among women with a previous or current diagnosis of depression, there was no difference between the control group and those taking fish oil capsules.

Similarly, 700 children from the study group who were assessed for cognitive and language development at 18 months of age showed no marked differences.