Most seafood is safe during pregnancy and actually recommended. The key is choosing low-mercury fish, cooking it thoroughly, and eating 2 to 3 servings per week (about 8 to 12 ounces total). A small number of high-mercury species should be avoided entirely, and raw or undercooked seafood is off the table until after delivery.
Why Seafood Matters During Pregnancy
Fish and shellfish are among the best dietary sources of omega-3 fatty acids, which support fetal brain development and may reduce the risk of preterm birth. Seafood also delivers iodine, a nutrient your body needs in higher amounts during pregnancy to produce thyroid hormones for both you and the baby. Insufficient iodine can impair normal brain development in the fetus.
Skipping seafood entirely to “play it safe” can actually work against you. The nutrients in fish are difficult to fully replace with other foods, and the benefits of eating low-mercury seafood consistently outweigh the risks for most pregnant people.
How Much Seafood to Eat Per Week
The FDA and EPA recommend 2 to 3 servings of low-mercury fish per week during pregnancy. One serving is about 4 ounces, roughly the size of the palm of your hand. That puts the weekly target at 8 to 12 ounces total.
Not all fish count equally toward that target. Fish in the “Best Choices” category (the lowest mercury levels) can be eaten 2 to 3 times per week. Fish in the “Good Choices” category, which carry moderate mercury levels, should be limited to 1 serving per week with no other fish that week.
Best Low-Mercury Choices
The safest options have very low mercury concentrations. Salmon is one of the best picks: fresh or frozen salmon averages just 0.022 parts per million (PPM) of mercury, and canned salmon is even lower at 0.014 PPM. Other excellent choices include shrimp, tilapia, cod, catfish, sardines, anchovies, herring, and pollock. Canned light tuna also falls in this category at 0.126 PPM, and you can safely eat 2 to 3 servings per week.
Cooked shellfish like shrimp, crab, and lobster are safe during pregnancy as long as they reach the proper internal temperature. These tend to be low in mercury and high in protein.
The Albacore Tuna Question
This is where many people get confused. Canned light tuna and albacore (white) tuna are not the same when it comes to mercury. Albacore averages 0.350 PPM of mercury, roughly three times more than canned light tuna. If you eat albacore, limit yourself to one serving that week and skip other fish.
Canned light tuna, by contrast, is a “Best Choice” and can be part of your regular 2 to 3 servings per week. If tuna is a staple in your diet, the type you buy matters.
Fish to Avoid Completely
Seven species carry mercury levels high enough that no amount is considered safe during pregnancy:
- Shark
- Swordfish
- King mackerel
- Tilefish (from the Gulf of Mexico)
- Marlin
- Orange roughy
- Bigeye tuna (often served as sushi-grade tuna steaks)
These are all large, long-lived predatory fish. Mercury accumulates up the food chain, so the bigger and older the fish, the more mercury it stores in its flesh. There is no safe serving size for these species during pregnancy.
Why Mercury Is Harmful
Mercury crosses the placenta and reaches the developing fetal nervous system. In high enough amounts, it can interfere with brain development, potentially affecting cognition, motor skills, and language later in childhood. The risk scales with exposure, which is why the guidance focuses on limiting overall intake rather than banning seafood outright. Low-mercury fish deliver the nutritional benefits without meaningful mercury exposure.
Raw and Undercooked Seafood
Sushi, sashimi, ceviche, raw oysters, and poke bowls made with raw fish all carry a risk of Listeria monocytogenes, a bacteria that’s particularly dangerous during pregnancy. Listeriosis can lead to miscarriage, stillbirth, premature delivery, and serious infections in newborns, including meningitis and blood infections. Late-term infections may cause lasting damage to the brain, heart, or kidneys.
Refrigerated smoked seafood is another source of Listeria that often catches people off guard. Products labeled “nova-style,” “lox,” “kippered,” or “smoked” that you find in the refrigerator section of the grocery store should be avoided unless they’re cooked into a dish like a casserole. Canned or shelf-stable smoked seafood is fine because the canning process kills the bacteria.
Cooking Temperatures That Matter
All fish and shellfish should reach an internal temperature of 145°F (62.8°C) before you eat it. For fin fish, that means the flesh should be opaque and flake easily with a fork. Shrimp and lobster should be firm and opaque. Clams, mussels, and oysters should be cooked until the shells open; discard any that stay closed.
A simple instant-read thermometer takes the guesswork out of it. Insert it into the thickest part of the fillet. If you’re ordering at a restaurant, ask for your fish to be cooked through rather than medium or rare.
What About Locally Caught Fish
If you eat fish caught by friends or family in local rivers, lakes, or coastal waters, check your state or local fish advisories. These waterways can contain mercury, PCBs, or other contaminants at levels that vary widely by location. When no advisory is available, limit locally caught fish to one serving per week and avoid eating any other fish that week.