A quick internet search of the terms “pregnancy” and “DHA” (commonly known as fish oil) yields nearly half a million results, most of them either extolling the latter for its virtues or (more likely) peddling it. Although many physicians advise their patients to increase DHA intake during pregnancy, little scientific evidence supports this advice. Now findings from a study published on March 21 in the Journal of the American Medical Association (paywall) suggest that DHA has little benefit during pregnancy.
DHA, or docosahexaenoic acid, is found in fatty fish such as salmon, herring, mackerel, anchovies, sardines, and tuna. Babies need DHA early in life to promote healthy brain and eye development.
The study, dubbed DOMInO for short (DHA to Optimize Mother Infant Outcome), was conducted in five Australian maternity hospitals between October 31, 2005, and January 11, 2008, and involved nearly 2,400 pregnant women. It was a double-blind, multicenter, randomized controlled trial – considered the gold standard in research study designs because it helps scientists determine whether a cause-effect relationship exists.
The researchers set out to determine whether increasing women’s DHA intake during the last half of pregnancy would improve their children’s neurological development. The pregnant women were divided in two groups: One group received 800 milligrams of DHA, and the other received a placebo (vegetable oil) daily. The women’s children participated in follow-up studies (at 18 months, 4 years, and 7 years of age) to assess the long-term effects of DHA.
At 18 months and 4 years of age, the two groups of children showed no differences in cognitive, language, or motor development.
At the seven-year point, the researchers assessed the children’s intelligence based on age-appropriate IQ tests. They found no differences between the two groups. In other words, the kids whose moms took DHA during pregnancy were no smarter than those whose moms didn’t.
Although DHA plays many roles in infant development, little evidence supports the need for increased DHA intake during pregnancy.