Fish and Pregnancy: A Careful Balance

19 Sep Fish and Pregnancy: A Careful Balance

Attention deficit/hyperactivity disorder (ADHD) is a diagnosis parents didn’t hear often prior to the 1980’s. It’s now a real concern with one in 10 children in the United States being formally diagnosed with the disorder. Recently, researchers published data suggesting that pregnant mother’s fish intake can influence a child’s risk of developing ADHD. But pregnant mom’s fish intake can be beneficial for babies too, so the trick may be to eat some fish, not too much, and not the kind of fish that contains the highest levels of mercury. The study: 788 pregnant mothers completed food diaries during pregnancy. The researchers also tested the tested hair samples from the mothers directly after delivering the babies to assess their mercury levels. Eight years later, each child’s teacher reported any ADHD-like symptoms they saw the children displaying in school.

The results: Findings suggest a connection between prenatal fish intake, mercury exposure, and ADHD diagnoses. Specifically, children of mothers who ate two or more servings of fish per week were about 60% LESS likely to develop certain ADHD symptoms. So eating fish is good for the future child.

But the researchers also found that elevated mercury in a mother was associated with children’s later ADHD symptoms. Mothers who had mercury levels that were 8 times higher than normal in their hair samples had children with a 60% greater chance of ADHD-like symptoms at age eight. Mothers who had less than 8 times as much mercury as normal had children with no increased chance of ADHD symptoms.

Bottom Line: Pregnant moms should eat fish for the protective factors that are passed onto their babies. However, to reduce mercury intake, be careful to avoid “big fishes” at the top of a food chain, where mercury is concentrated, such as tuna, marlin, orange roughy, shark, and swordfish, among others. Haddock, salmon, and other smaller fish contain less mercury and are safer during pregnancy.

Sagiv, S. K., Thurston, S. W., Bellinger, D. C., Amarasiriwardena, C., & Korrick, S. A. Arch Pediatr Adolesc Med. 2012;166(12):1123-1131.