Fish is a very healthy food with lots of omega-3 fatty acids that are necessary for the brain development of a growing fetus. Unfortunately, some types of fish contain high levels of mercury, a highly toxic chemical that can cause serious birth defects if a pregnant woman consumes too much of it. Fish with the highest levels of mercury should not be consumed at all during pregnancy, while those with the lowest levels can be safely consumed twice a week. Fish with intermediate levels of mercury should be eaten in moderation during pregnancy. The following is a grouping of the most common types of fish based on their mercury content.

Fish with the highest mercury levels
Avoid these fish entirely during pregnancy

• Grouper
• Marlin
• Orange roughy
• Tilefish
• Swordfish
• Shark
• Mackerel (king)

Fish with medium to high mercury levels
Eat no more than three, 6-oz servings per month

• Saltwater Bass
• Croaker
• Halibut
• Tuna (canned, white albacore, fresh bluefin, ahi)
• Sea trout
• Bluefish
• Lobster (American/Maine)

Fish with low to medium levels of mercury
Eat no more than six, 6-oz servings per month

• Carp
• Mahi Mahi
• Crab (Dungeness, blue, snow)
• Snapper
• Herring
• Monkfish
• Perch (freshwater)
• Skate
• Cod
• Tuna (chunk light canned, fresh Pacific albacore)

Fish with the lowest levels of mercury
Eat up to two, 6-oz servings per week

• Anchovies
• Butterfish
• Calamari (squid)
• Caviar (farmed)
• Crab (king)
• Pollock
• Catfish
• Whitefish
• Perch (ocean)
• Scallops
• Flounder
• Haddock
• Hake
• Herring
• Lobster (spiny/rock)
• Shad
• Sole
• Crawfish
• Salmon
• Shrimp
• Clams
• Tilapia
• Oysters
• Sardines
• Sturgeon (farmed)
• Trout (freshwater)

For more information on proper nutrition during pregnancy, see the Healia Health Guide on Pregnancy. If you have questions about whether a certain food is OK to eat, ask the people in the Healia Health Community for Pregnancy.

Related blog posts: Tips for Eating Healthy During Pregnancy: what to eat when you are pregnant
Tips for Eating Healthy During Pregnancy Part 2: 13 foods and beverages to avoid when you are pregnant

_{Source: American Pregnancy Association, Mercury Levels in Fish, updated 3/07. http://www.americanpregnancy.org/pregnancyhealth/fishmercury.htm}

_{Photo: hyku, Flickr, Creative Commons}