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Fish oil during pregnancy led to ‘stronger kids,’ but was the difference clinically meaningful?


4 Star


Fish Oil Pills During Pregnancy Might Mean Stronger, Healthier Kids

Our Review Summary

vitamin DThis HealthDay story describes a study published in the British Medical Journal that looked at whether pregnant women who took fish oil supplements in their third trimester produced healthier children based on their growth statistics and body mass index, compared to mothers who did not.  The study was a high-quality randomized controlled trial of the effects of fish oil during pregnancy on asthma in children, which looked at effects on body mass index as a secondary outcome measure.

The story included multiple independent sources to provide perspective, and it included a few key details about the study. While it provided the scope of the benefit of taking fish oil, it could have gone a step further to explain if those measured benefits really mean much for children’s health.


Why This Matters

There is great interest in understanding the effects of interventions during pregnancy on the health of the offspring, but such studies are difficult to conduct, since assessing outcomes that occur years following the pregnancy can be a challenge.

Although the effects of fish oil supplements on children’s growth was not the primary intention of this trial, the results do suggest that mothers who take the supplements during their last trimester have children whose body mass index and body measurements for up to six years of age are better than the children of mothers who didn’t take the supplements.  If a simple supplement can actually lead to that kind of improvement in children’s that would be an important finding for public health.


Does the story adequately discuss the costs of the intervention?

Not Applicable

This story doesn’t mention the costs of the fish oil supplements it appears to support. However, the cost of such supplements is reasonable and the period in which they’re recommended is short — the last trimester of pregnancy — making cost a lesser concern than in some cases.

Does the story adequately quantify the benefits of the treatment/test/product/procedure?


The story explains the benefit this way:  “At age 6, children whose mothers took fish oil supplements while pregnant had a 395 grams higher total mass, 281 grams higher lean mass and 10 grams higher bone mineral content than children whose mothers who took olive oil during pregnancy, the findings showed.”

This is sufficient, but the story could have provided some context on whether these numbers are clinically meaningful. Is 395 grams (less than a pound) a big deal? What about 10 grams more bone mineral content? Is that change big enough to reduce fractures, for example?

Does the story adequately explain/quantify the harms of the intervention?

Not Satisfactory

The story didn’t discuss any risks of taking fish oil. But these include belching, bad breath, heartburn, nausea, loose stools, rash, and nosebleeds. For pregnant women who have to be vigilant about even seemingly harmless side effects (nausea can be a serious symptom in the third trimester, for example), these details are important.

Does the story seem to grasp the quality of the evidence?


The story points out that this study used both an experimental and control group to test their hypothesis about fish oil supplements, and mentioned the large number of participants who took part — 736 pregnant women. It also included some of the study’s limitations and explained that growth wasn’t the primary measurement researchers were following, it was actually development of asthma.

Does the story commit disease-mongering?


No disease mongering here.

Does the story use independent sources and identify conflicts of interest?


The story provides comments from independent sources unaffiliated with the research. We did not detect any conflicts of interest that should have been disclosed.

Does the story compare the new approach with existing alternatives?

Not Applicable

Since there is little existing research in this area, the inclusion of another alternative would be difficult.

Does the story establish the availability of the treatment/test/product/procedure?


Fish oil supplements are readily available.

Does the story establish the true novelty of the approach?

Not Satisfactory

The story made very brief mention of other research in this area.

Past trials of fish oil supplements during pregnancy or breast feeding, using different designs, doses, and follow up periods, have shown mixed results. The story would have been strengthened by some context, including findings of other studies and what is known of a possible mechanism for an effect of fish oil on growth of offspring.

Does the story appear to rely solely or largely on a news release?


The story doesn’t appear to rely on a news release.

Total Score: 6 of 8 Satisfactory


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