Nurturing life Your reference in perinatal nutrition, from pregnancy to childhood

Why does certain seafood pose a risk to pregnancy?

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By : Nurturing Life's Nutrition Team | Montreal Diet Dispensary
— Updated on :

Some seafood may contain bacteria dangerous to pregnant women. Special attention should thus be paid to their safety. As some seafood may have a high content of mercury, the amount and type of consumed seafood should also be considered.

Given its beneficial nutrients for the pregnant woman and her baby, seafood is not to be excluded from the diet in pregnant women. On the other hand, those containing high levels of mercury should be avoided due to potential toxicity to the fetal brain, which could cause long-term neurological problems.

Seafood that contains small amounts of mercury include oysters, mussels, crab, lobster, clams, scallops and shrimp. Health Canada recommends two servings of fish (for omega-3) with low mercury content per week. Although seafood does not contain as much omega-3 as fish, it is possible to vary the menu, replacing fish with seafood.

In addition, bacteria can lodge in seafood, some of which are particularly dangerous to pregnant women: Listeria, E. coli, Salmonella and Vibrio. These microorganisms can contaminate oysters, mussels and clams, causing food poisoning. Severe food poisoning can affect the fetus in the following ways: intrauterine growth retardation, birth defects, premature birth. Before consuming seafood, we must ensure that they are not toxic.


  • Consume the freshest seafood
    • Those whose shell is open before cooking and those whose shell remains closed after cooking should be discarded.
    • Do not consume the tomalley (green substance in the cavity of the lobster) because it may contain natural toxins and contaminants.
    • Refrigerate or freeze the seafood as soon as you are back from the store.
  • Use proper cooking temperature to kill bacteria: 74 oC (165 oF)
  • Avoid eating raw seafood.
  • Buy your seafood only from a trusted supplier.
  • Avoid “U-pick” without having first checked that the area is opened to harvesting, to avoid biotoxins (French only).

To learn more about which seafood can be eaten safely during pregnancy, see the next edition.