For the last several years, many pregnant women have been seriously limiting -- or scrupulously avoiding -- fish in their diets. This is largely due to a 2004 advisory from the Food and Drug Administration and the Environmental Protection Agency recommending that pregnant women limit fish consumption to 12 ounces -- roughly two average meals -- per week, and that they eat varieties of fish and shellfish that are low in mercury (here's the whole advisory).
Unfortunately, the nuances of this recommendation were lost as it filtered into popular knowledge. What many women heard were the terms "mercury" "risk" and "harm" and on this basis ate much less fish than the advisory permitted - or none at all. A 2007 study showed that awareness of this warning drove 56 percent of pregnant women to needlessly reduce their fish consumption.
The problem with eating less fish during pregnancy is that it potentially deprives the developing fetus of vital nutrients. The omega-3 fatty acids, which are present in nearly all fish and particularly abundant in cold water varieties such as wild salmon, sardines, herring and black cod, are essential for healthy development of a baby's brain and nervous system. No other common food source delivers these nutrients in such quantity.
The crucial point: Research now suggests that the benefit to a baby's neurological health from omega-3s appears to far outweigh the potential for harm from small amounts of mercury in fish tissues.