Seafood is also a major issue as far as your diet goes when you're pregnant. The big fish like shark, swordfish, tile-fish and king mackerel should not be eaten when you are pregnant. These fish are likely exposed to and contain mercury, due to industrial pollution, and so could cause problems for your baby's brain and nervous system development.
However, shrimp has lower incidence of mercury and so is safe if cooked thoroughly and you restrict intake to no more than 12 ounces a week. Crab is very low in mercury and also can be eaten in the quantity of 12 ounces in a week.
You can have 6 ounces a week of canned light tuna too. Remember the 12 ounce limit on the seafood that you can eat during pregnancy means total. You can only have a total of 12 ounces altogether, so that 6 ounces of tuna is part of the 12 ounce weekly total.
It should be noted too that white albacore tuna should be avoided because it has higher levels of mercury.
Other fish that can be included in the 12 ounce a week limit of seafood include salmon, pollack, sardines, talapia and catfish.
Also do not eat refrigerated smoked seafood often labeled "nova-style", "lox", "kippered", "smoked" and "jerky" often made from salmon, trout, whitefish, cod, tuna and mackerel. Unless these are included in a dish that's thoroughly cooked, you should totally avoid them.
Of course, sushi, which contains raw fish, should be avoided entirely.