Taking fish-oil supplements during pregnancy does not seem to have any beneficial effect on your baby's brain development, contrary to what some fish-oil-supplement marketing companies claim.


What's more, fish-oil supplements don't seem to lessen your risk of developing post-natal depression, either – despite some claims that they might.

That's the conclusion of researchers at the South Australian Health and Medical Research Institute (SAHMRI), whose decade-long study confirms the findings of a smaller study in 2010.

Fish-oil supplements don't effect baby brain development (but fish oils do)

Fish-oil supplements contain omega-3 and omega-6 fatty acids. And your baby-to-be definitely does need adequate amounts of omega-3 and omega-6 fatty acids, particularly in the final trimester when much of the brain development occurs.

But the vast majority of pregnant women are perfectly able to supply their baby with adequate supplies omega-3 and omega-6 fatty acids simply by eating omega-3 and omega-6-rich foods, such as oily fish (salmon, sardines and mackerel), and, to a lesser extent, dark green leafy vegetables, flaxseed, nuts, seeds, soya beans, seeds and vegetable oils.

What the researchers were interested in is whether taking fish-oil supplements could give your baby the edge in terms of brain development. In other words, would your baby be brainier than he or she would otherwise be if you took fish-oil supplements while you were pregnant?

The researchers studied hundreds of women through their pregnancy and gave each of them either fish-oil supplements or a placebo (dummy pills). They then tracked their progress until each woman's child was 7 years old.

"Overall. we found... no benefit," says the SAHMRI's Dr Jcquieline Gold. "So the babies in this study don't seem to have any benefit to their brain development from their mothers taking fish oil.

"Mainly we looked at their intelligence. So, at 18 months, we did some assessments with them, and again when they reached 4 years and just now when they turned 7."

Fish-oil supplements have no effect on risk of post-natal depression

The researchers also looked at whether fish-oil supplements decreased the rate of post-natal depression.

"There was no effects there either," Dr Gould says.

"But we did find slightly lower rates of depression in both groups – so it could be that being part of a study where we had research nurses calling mums regularly might have even prevented depression.

So is there any point taking fish-oil supplements when you're pregnant?

There's certainly no harm in them – and, in very rare cases, where your body levels of omega-3 and omega-6 fatty acids (the fatty acids that are encapsulated in fish oil supplements) are deficient, they may be helpful.

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But taking them is not going to make your baby any brainier

One thing that the study did throw up, however, is that, according to Dr Gould, "the length of pregnancy increased just a little bit in the fish-oil group, and that actually meant there were slightly fewer babies born very pre-term".

"We still have to do more work to find out whether or not this is a true effect of the fish oil," she adds, "but that would be quite a significant benefit, if it is."

Interestingly, this is an additional finding the 2010 study also highlighted: new mums taking fish or vegetable oil supplements were less likely to give birth before 34 weeks.

So, the take-home message here seems to be: take the fish-oil supplements if you'd like to (and maybe especially if you're not fond of omega-3 and omega-6-rich foods such as tuna, pumpkin seeds and nuts) but just don't expect them to turn your baby into the next Einstein.