Response

We thank Dr Schwalfenberg for his interest in Motherisk Update. Our recent review regarding ω-3 fatty acids during pregnancy1 begins with a clinical question, as is customary with Motherisk Updates. The question was about whether ω-3 supplementation should be recommended to pregnant women and not whether it affects the human brain, photoreceptors, and cell functions in general. Therefore, the focus of the review was to look at the available interventional trials of ω-3 supplementation during pregnancy, which sometimes contradict what was previously believed based on observational studies.

Our review delineates the possible areas of benefit, but concludes, “Until evidence accumulates, no recommendation should be made to encourage pregnant women to take ω-3 fatty acid supplements.” A similar conclusion was drawn in another recent, similar paper.2 A meta-analysis of the highest-quality randomized control trials on ω-3 supplementation during pregnancy (published after the submission of our review and hence not included) concluded that ω-3 supplementation did not influence the rates of preterm deliveries, preeclampsia, eclampsia, or infants with low birth weights.3 There was also no influence on birth weight. Adding these findings to our discussion strengthens our conclusion that there is no clear benefit of ω-3 fatty acid supplementation to maternal or infant health.

To the specific points raised by Dr Schwalfenberg: reference 10 is used in the article for both observational and interventional trials because it is a review article describing both. The second point concerns the prevalence of preeclampsia in the paper by Smuts et al4; it is a matter of basic statistical analysis. The “50% risk reduction” in prevalence between groups is not statistically significant, with χ² analysis yielding P=.3. Finally, the relevant sources of funding to the authors and the Motherisk program and potential conflicts of interest were fully disclosed in the article. These are routinely found at the end of the article in the Motherisk box.

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