Of all the strong food cravings that newly pregnant women may have, salty fish is a surprisingly popular one. Women’s sodium levels drop when they're pregnant, especially during their first trimester; however, as much as you may want to indulge in some delightfully salty raw oysters, you should keep your hands off of them while you're pregnant.
Raw oysters, prepared correctly from a trustworthy and clean source, are usually healthy for you, since they contain vitamin B12, vitamin D, iron, and more. However, when you’re pregnant, any type of raw seafood is not safe to eat, since even a tiny risk of ingesting food-based bacteria could seriously harm you or your baby.
You should also avoid fish that contain high mercury levels, such as bigeye tuna, king mackerel, marlin, orange roughy, swordfish, shark, and tilefish. However, two to three servings of cooked fish per day can help prevent postpartum depression and lower the risk of heart disease in kids, so feel free to eat cooked shrimp, crab, salmon, and yes, oysters.