have tuna or swordfish or many fish because of high levels of mercury you don't want transferred to your fetus. what do you say? >> yeah, fascinating. so it is true that mercury is bad for your fetus and that's the very good reason to avoided large fish but at the same time, omega 3s are good for your baby's i.q. and those are the same, those are found in the same kinds of fish that have a lot of mercury. you're facing a little bit of a trayoff. what are you in the book you want to have fish which are low in mercury but high in oy mega3s like herring, sardines, oily fish we're not eating a lot of but should have more. alisyn: those are the not fish found at sushi bars. >> no. alisyn: doctor, do you think you could eat sushi free and clear when you're pregnant? >> absolutely you can have sushi. there is entire nation called japan that eat sushi frequently. i wouldn't go crazy. i wouldn't have sushi every day for lunch. it is something you do in moderation. you do have to keep in mind