Pregnant women are bombarded these days with recommendations about what they can and cannot eat.
Unpasteurized dairy? No.
Deli meats and cheeses? Definitely not.
Seafood?…It’s a bit less clear.
We know that Omega 3 fatty acids from seafood are supportive to baby’s neurologic development. We also know that high levels of mercury can harm baby’s developing brain. Beyond this, the available data is less straightforward. There is a British study showing that infants born to mothers who consumed only small amounts of seafood during pregnancy were more likely to have suboptimal neurodevelopment as compared to infants born to mothers who ate larger amounts of fish. The women in the lower consumption group ate about 12 ounces of fish per week. But 12 ounces per week is the upper limit of the current recommendation from the FDA and the EPA. Confusing, right? Why isn’t it simply that more low-mercury fish is better?
The trouble is that the current EPA and FDA guidelines (2 6-ounce servings per week) have not been updated since 2004. Also, we have become more aware of how much of the fish we consume may contain harmful pesticides from agricultural runoff and other chemicals used in fish farms. So this has left pregnant women and their doctors in the position of having to come up with what they believe to be best and safest recommendations regarding seafood consumption. Many obstetricians are concerned that their patients are so frightened by the potential for harm that they are eating far less fish than we think is beneficial.
What I think is a reasonable recommendation is to strictly limit your fish consumption to low-mercury species and to have a goal of having about twelve ounces of wild fish per week. However, if you are having local fish or farmed fish, limit your consumption of that fish to six ounces in that week and try to make up the difference with wild fish. If you don’t know where the fish has come from, assume the worst. That system will limit both mercury and pesticide levels while still allowing for the dietary benefits of seafood. And of course, no raw or rare fish at all… I know, I know. More torture.
You and your healthcare provider should also discuss whether a DHA supplement made from wild, small fish is a suitable complement to your prenatal vitamin regimen. This may provide some of the benefits of eating whole fish without the worry about source, type or tolerability to nauseous tummies.
NYC has produced and handy guide to the mercury content of some common types of fish here.