There is much confusion about fish consumption during pregnancy. Fish contains important Omega-3 DHA, critical to fetal brain development. However, some fish (shark, tilefish, swordfish, king mackerel) contain levels of mercury that can be harmful to a developing fetus.
  Pregnant women should eat 2-3 servings (about 12 ounces) of fish per week, and avoid fish that may be high in mercury content.  Pregnant women unable to eat 2-3 servings per week should take an Omega-3 DHA supplement.  Eating whole fish is preferable to supplements because whole foods offer complete nutritional contents and its benefits.