Pregnant women should eat at least 12 oz of fish each week because of healthy omega-3 fatty accids that promote baby's brain growth. They should avoid fish with increased mercury levels. For most people, the risk of mercury by eating fish and shellfish is not a health concern. Yet, some fish and shellfish contain high levels of mercury that may harm an unborn baby or young child's developing nervous system.
These are recommended because they are high in omega-3 fatty acid (good!) and low in mercury: Salmon, Anchovies, Herring, Sardines, Trout, Atlantic and Pacific mackerel
Do not eat the following because they contain high levels of mercury: Shark, Swordfish, King Mackerel, Tilefish.
Beyond seafood, other sources of omega-3 fatty acids include:
Foods. Flaxseed — ground seeds or oil — canola oil, walnuts, sunflower seeds and soybeans (edamame) are all good sources of omega-3 fatty acids.
Fortified foods. Yogurt, milk and eggs can be fortified with omega-3 fatty acids.
Supplements typically contain fish oil or omega-3 fatty acids from marine plant sources. Many prenatal vitamins also contain DHA. Talk to your doctor before taking any supplement.
Researchers have not yet determined whether supplements can promote fetal brain development. Pregnant women can get omega-3 fatty acids from many sources, most experts recommend eating recommended seafood for this purpose.