Eating Fish While Pregnant: The Good and the Bad

Pregnant fish

Seafood, both fish and shellfish, can be a healthy part of anyone’s diet. It has high amounts of good quality protein and is a great source of the minerals iron and zinc, and of vitamin D and omega-3 fatty acids, which are all things everyone needs to have in their diet. Fish is also low in saturated fat, something we should try to cut out of our diet.

These nutrients are especially important for pregnant women, which makes eating fish regularly a great idea. Fatty acids such as omega-3s are very important for the good development of your baby. One fatty acid in particular is docosahexaenic acid (DHA), which promotes brain growth. Fish are rich in DHA, which does not occur in large amounts in other foods.

But during pregnancy, eating fish comes with a possible hazard: mercury. Certain types of fish can contain high levels of mercury. These mercury levels are not a problem for adults, but too much mercury in your bloodstream while you are pregnant can damage your baby’s growing brain and nervous system.

We’ve covered this topic before on this blog, but it is always good to revisit the issue.

Which Fish Is Good Fish?

This intersection between good nutrition and mercury means that pregnant women get the confusing advice to eat fish during their pregnancy, but not too much fish and not the wrong types of fish.

The wrong fish are the larger fish who live by eating other fish; including species such as shark, swordfish, king mackerel, and tilefish. The U.S. Food and Drug Administration and the Environmental Protection Agency advise women of childbearing age and young children to avoid eating these four types of fish because the levels of mercury they contain. Pregnant women are also advised to avoid striped bass and bluefish because of contamination with industrial pollutants called PCBs.

The fish that are good to add to your diet include types such as salmon, sardines, trout, shrimp, and catfish.

The FDA recommends that pregnant and nursing women eat up to 12 ounces each week of a variety of seafood. That is about two meals with fish as the entrée.

Eating canned tuna—probably the most commonly consumed type of fish in the United States and the most economical—is more controversial. The FDA says it is okay to eat up to 12 ounces per week of canned light tuna, but also says pregnant women should limit their intake of canned albacore tuna to 6 ounces per week. On the other hand, Consumer Reports magazine has advised pregnant women to avoid all canned tuna.

If you like to fish, or know local fishermen who give you some of their catch, be careful. Pay attention to advisories from local health departments about the safety of local fish. The FDA says you can eat up to 6 ounces a week of local fish, but if you do, then don’t eat any other fish that week.

Mercury is not the only problem with seafood. Pregnant women should not eat uncooked seafood of any kind because of the risk of bacterial contamination. This means no raw clams, no raw oysters, and no sushi or sashimi.

If you’re not sure which are the good fish and which are the bad ones, Purdue University has created free iPhone/iPod apps that can help you track your seafood consumption and estimate your intake of omega-3s, mercury, and PCBs.

Don’t Give Up Fish!

If, after reading this, you decide to swear off eating fish for the duration of your pregnancy and your nursing, think again. The safe fish discussed here are really good for you and your baby. An observational study done on 2,000 pregnant women in Spain has found that children of women who ate more servings of fish each week had children with higher cognitive scores and fewer symptoms of autism. The study also found no issue with mercury in the children.

Valerie DeBenedette
Valerie DeBenedette is an experienced health and medical writer who lives about an hour north of New York City with a dog that is smaller than her cat. Her work has appeared in magazines, newspapers, newsletters, and on websites. She is a member of the National Association of Science Writers.

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