[Fish oil in pregnancy: can it prevent asthma in children?].

Taking fish oil supplements in the third trimester of pregnancy was associated with significantly less wheezing or asthma in the child at the age of 3-5 years, according to a randomized clinical trial by Bisgaard et al., NEJM 2017. However, the results of this study should be interpreted with caution. The primary end points were modified at a late stage in the study, and two primary end points, eczema in the first 3 years of life and allergic sensitization at 18 months of age, were demoted to secondary end points, and showed no significant effect of treatment. Furthermore, the age range for the published primary end point, persistent wheeze, differed from that in the protocol. Additional concerns include the emphasis on outcomes by omega-3 fatty acid levels in the blood, a post hoc subgroup analysis not included in the protocol. In our opinion, this study does not justify advising routine fish oil supplements in pregnancy.