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URMC / Patients & Families / Health Matters / April 2016 / Fish Tales: What’s the Story on Eating Fish During Pregnancy?

Fish Tales: What’s the Story on Eating Fish During Pregnancy?

Is fish safe to eat during pregnancy? It’s a question many expectant mothers ask their doctors, and it’s gotten more attention thanks to two studies that offered seemingly different takes. One study shows that eating fish during pregnancy is good for babies’ brain development; another suggests eating a lot of fish could be related to childhood obesity. The Food and Drug Administration has a tool to help women know which types of fish are safe to eat and how often, as well as the varieties they should avoid when pregnant or trying to become pregnant.

UR Medicine Ob/Gyn chair Dr. Eva Pressman answers some commonly asked questions about eating fish during pregnancy.

fresh fish with lemons

Health Matters: Why is eating fish during pregnancy such a hot topic?

Pressman: Nutrients in fish have numerous health benefits for pregnant women and their babies. But fish is a common cause of exposure to mercury and other neurotoxins that can be harmful to the fetus. We advise pregnant women to eat fish for its benefits, following the Food and Drug Administration and the Environmental Protection Agency’s established guidelines, which recommend two to three servings (8-12 ounces) of fish per week.

Health Matters: What are the benefits to eating fish?

Pressman: The Omega-3 fatty acids found in many kinds of fatty fish are good for everyone. For pregnant women, they play an important role in fetal development. Omega-3 is critical for the development of the brain and eyes. One study showed that pregnant women who eat at least 12 ounces of oily fish per week have children with better childhood IQ scores, fine motor coordination, and communication and social skills.

Health Matters: Why do we need to limit fish consumption?

Pressman: Fish swimming in polluted waters ingest pollutants, including mercury, which have been shown to be harmful to humans. And larger fish eat smaller fish that contain mercury so the effect multiplies. Mercury in the environment turns into methylmercury in the water—the type of mercury found in fish. Too much exposure to methylmercury can be harmful to the brain and nervous system.

Another reason comes from one of the recent studies, which found that children of women who ate more than three servings of fish per week had a higher risk of childhood obesity.

pregnant woman walking outside with partner

Health Matters: Are some fish more risky to eat than others?

Pressman: In general, when you’re worried about pollutants, the longer a fish lives the more contaminants it can accumulate. The FDA and EPA caution consumers to avoid the four types of fish highest in mercury: tilefish from the Gulf of Mexico, shark, swordfish, and king mackerel. They recommend that pregnant women eat salmon, shrimp, pollock, light canned tuna, tilapia, catfish and cod, and to limit white (albacore) tuna to 6 ounces a week. And, when eating fish caught in fresh waters (streams, rivers, and lakes) pregnant women should pay attention to fish advisories for those areas. If the information isn’t available, limit fish from these areas to 6 ounces a week and don’t eat other fish that week.

Health Matters: What do you make of the two recent studies; are they contradictory?

Pressman: Taken together, these studies show that fish consumption can be good for pregnant women and their babies—but too much of a good thing isn’t beneficial for either of you. More research needs to be done on why greater consumption of fish is related to weight gain; the study shows an association, not a direct cause-and-effect situation. The question remains: Is there something in fish that causes weight problems in babies later on, or do children in the countries that eat more fish tend to consume more and thus gain more weight?

Health Matters: So do you recommend that women eat fish while pregnant or breastfeeding

Pressman: Yes, women can continue to enjoy fish and get the benefits for their babies' development, but consume it according to the recommended guidelines. Omega-3 vitamins are passed to nursing babies through breast milk, so fish remains an important part of your diet while breastfeeding. The same guidelines on consumption apply—two to three servings a week, for a maximum of 8 to 12 ounces.

Health Matters: Are there any foods women should avoid completely during pregnancy or breastfeeding?

Pressman: Moderation is the answer to most questions about diet and pregnancy. In this country, our food is fairly well-regulated so there is no food I say women absolutely can’t have. Soft unpasteurized cheeses that may have listeria are a problem for pregnant women in other countries, but not here.

The bottom line is this: If food fears are causing you to not get enough of something you need or too much of it, that’s not as good as eating a balanced diet. As long as you eat things in moderation, nothing is off limits.

Eva Pressman, M.D.


Eva Pressman, M.D., is the Henry A. Thiede Professor and Chair of the Department of Obstetrics and Gynecology at the University of Rochester. Her research focuses on nutrition in pregnancy, as well as weight gain, obesity, and diabetes in pregnancy.


Lori Barrette | 4/11/2016

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