In general, people rarely if ever get sick eating Sushi. But raw seafood is potentially risky because it can contain parasites such as tapeworm. Freezing and cooking kills, most parasites, and many if not most Japanese restaurants that specialize in sushi use frozen rather than fresh fish. You may want to ask your restaurant before ordering Sushi if it has previously been frozen or not.
One concern about seafood, raw or cooked, is PCB and chemical contamination. If you want to eat fish during your pregnancy, contact your local health department or office of the Environmental Protection Agency (EPA) for a list of fish in your area that haven't been contaminated with toxins. You may also want to avoid certain fish with higher mercury levels.
As a general rule, ocean fish such as tuna, sea bass, sole, flounder, and snapper are safer than river and lake varieties. When eating out at any restaurant, order your fish well cooked. Many upscale eateries lightly sear fresh fish on the outside, then serve it rare.
Some types of sushi, such as California rolls (which contain steamed crab) and cooked eel, are fine to eat while you're pregnant and if you avoid eating the kinds that contain raw seafood you are sure that you have no problems.
In both the United States and Japan, many more people get sick from eating fish served at home than from eating fish at sushi restaurants. For seafood safety at home, the Food and Drug Administration has a few tips. According to the FDA's 1997 Food Code, you should cook most seafood to an internal temperature of 145 degrees Farenheit (63 degrees Celsius) for 15 seconds.
If you don't have a thermometer, the guidelines listed below can help you to determine whether seafood is done.