Fish with Mercury: Fish that contain high levels of mercury should be avoided. Mercury consumed during pregnancy has been linked to developmental delays and brain damage. These include: shark, swordfish, king mackerel, and tilefish. Canned, chunk light tuna generally has a lower amount of mercury than other tuna, but still should only be eaten in moderation.

Fish Exposed to Industrial Pollutants: Avoid fish from contaminated lakes and rivers that may be exposed to high levels of polychlorinated biphenyls. This is primarily for those who fish in local lakes and streams. These fish include: bluefish, striped bass, salmon, pike, trout, and walleye. Contact the local health department or Environmental Protection Agency to determine which fish are safe to eat in your area. Remember, this is regarding fish caught in local waters and not fish from your local grocery store.

Fish with PCBs: Polychlorinated biphenyls (PCB) is associated with memory difficulties and lower IQs. Fish included in the PCB warning include: bluefish, stripped bass, salmon, pike, trout, walleye. (This may be a regional warning since some of these are fresh water fish. Know where your fish comes from and who to ask.)

Unpasteurized Milk: Un pasteurized milk may contain a bacteria called listeria, which can cause miscarriage. Listeria has the ability to cross the placenta and may infect the baby leading to infection or blood poisoning, which can be life-threatening. Make sure that any milk you drink is pasteurized.

Alcohol: There is NO amount of alcohol that is known to be safe during pregnancy, and therefore alcohol should be avoided during pregnancy.

Unwashed Vegetables: Yes, vegetables are safe to eat, so you still need to eat them. However, it is essential to make sure they are washed to avoid potential exposure to toxoplasmosis. Toxoplasmosis may contaminate the soil where the vegetables were grown.

Caffeine: Although most studies show that caffeine intake in moderation is OK, there are others that show that caffeine intake may be related to miscarriages. Avoid caffeine during the first trimester to reduce the likelihood of a miscarriage. As a general rule, caffeine should be limited to fewer than 200 mg per day during pregnancy.

Deli Meats: Due to the risk of listeriosis, you will want to ensure that all deli meats are thoroughly reheated. The internal temperature of the meat should be 165 degrees.

Liver: Excessive amounts of vitamin A in non-beta-carotene form can cause birth defects. The food in this category is liver.

Raw Meat, shellfish and Seafood: These can can infect you with salmonella or toxoplasmosis such as rare red meat and sushi

Soft Cheeses: Because of the way these cheeses are made, they may contain harmful bacteria. Imported soft cheeses may contain bacteria called Listeria, which can cause miscarriage. Listeria has the ability to cross the placenta and may infect the baby leading to infection or blood poisoning, which can be life-threatening. Unpasteurized cheeses include: brie, feta, Camambert, bleu cheese, queso blanco, queso fresco etc.

Raw Eggs: Salmonella is the risk from raw egg. Foods to avoid include: cake batter, raw cookie dough, homemade ice cream, custards, mayo, egg nog or Hollandaise sauce. If the recipe is cooked at some point, this will reduce the exposure to salmonella. Commercially manufactured ice cream, dressings, and eggnog are made with pasteurized eggs and do not increase the risk of salmonella. Restaurants should be using pasteurized eggs in any recipe that is made with raw eggs, such as Hollandaise sauce or dressings.

Foods with nitrates as a preservatives: For example-  hot dogs, processed meats

Here are additional reading a great list of foods to eat while pregnant and important vitamins to ensure you are getting while pregnant.

Resources and Further Reading:

http://www.americanpregnancy.org/pregnancyhealth/foodstoavoid.html