Many of us struggle with this as there are many stories related with mercury. Adding seafood to your diet is essential as fish has so many nutrients and key ones are Omega 3 fatty acids that are difficult to find in other foods.
So that you can consider adding them in to your diet even though you don't eat fish normally but need to be very careful when choosing fish. Mainly due to mercury content in certain sea food.
Mercury is everywhere but when mercury settles into water, bacteria convert it into a form called methylmercury. Fish absorb methylmercury from the water they swim in and the organisms they eat. Methylmercury binds tightly to the proteins in fish muscle and remains there even after the fish is cooked. This is long story in short form but now you know why you need to be careful.
Now the scary part, your body easily absorbs methylmercury from fish – and when you're pregnant, methylmercury crosses the placenta. Many studies have shown that exposure even to lose doses of methylmercury during pregnancy can impair a baby's growing brain and nervous system. The results can range from mild to severe. According to the Environmental Protection Agency (EPA), cognitive skills (like memory and attention), language, motor skills, and vision may be affected.
Babies in utero, infants, and young children are generally thought to be most vulnerable to damage from methylmercury. That's why women who are pregnant, thinking of becoming pregnant, or nursing need to pay particular attention to the kind of fish they're eating.
Now let's be clear on what is good to eat, the U.S. Food and Drug Administration (FDA) and the EPA advise women of childbearing age and young children not to eat four high-mercury species: swordfish, shark, king mackerel, and tilefish from the Gulf of Mexico. Also its better to avoid canned tuna as well.
When it comes to daily intake of Omega 3, The 2015 U.S. Dietary Guidelines suggest that pregnant and breastfeeding women get 250 milligrams of EPA and/or DHA a day by eating 8 ounces of fish that are rich in omega-3s each week. Because of Omega 3 is important some women choose the supplement but most have shown no significant benefits from these supplements.
You can find omega-3 supplements in liquid, soft chews, and soft gel form, and some are flavored to mask the fishiness. Omega-3 supplements are mercury-free. Many contain fish oil, but mercury is not stored in fatty tissue, so it's not in the oil.
Note: Some women turn to cod liver oil as a source of omega-3s. If you go this route, check the label to make sure you're not exceeding the recommended dosage of vitamin A for pregnant women. (Vitamin A can be toxic at high doses.)
Somehow it's better to choose carefully and get advice from your doctor on this if you have more questions.