The main line is that you can still eat many of your favorite foods, including seafood, while pregnant. It is only necessary to ensure that mussels and other shellfish are safe to consume. Pregnant women should not eat any food without knowing what is in it. The best way to do this is by reading labels and checking the internet for information about possible contaminants in each ingredient. Seafood is the number one source of contamination for pregnant women because they don't know what is in the food. Most seafood companies are not required to tell you what is in their products. Even if they did, some things such as mercury and polychlorinated biphenyls (PCBs) are harmful even at low levels of exposure. For example, studies have shown that women who ate two servings of fish per week during pregnancy were less likely to have a child with autism compared with women who didn't eat fish. This means that women need to avoid eating any amount of contaminated seafood since this could lead to problems for the developing baby. Mussels are an exception because they are known to contain high levels of arsenic. However, most people are able to handle a dose of arsenic every day without any problems. Only people who have an allergy or intolerance to metal might experience some side effects after eating mussels. These include stomach pain, diarrhea, and skin rashes.