The sushi i eat which has raw salmon and tuna has been previously frozen to kill any parasites. will it still be harmful to eat when pregnant? why?

Freezing doesn't: Kill everything!in fact, most parasites, during certain stages of their life cycle, can survive freezing and will wake up in your tummy.

Sushi & pregnancy.: Sushi should be avoided during pregnancy for two reasons. (1) risk of bacterial infection complicating the pregnancy. (2) risk of exposure to mercury complicating the pregnancy. Certainly not worth the risk during pregnancy. Cooked sushi or vegetable-only sushi should be fine, but then we'd worry about the person making the sushi having washed his hands after handling raw fish.