Seafood is not bad for pregnancy. In fact, it’s one of the most nutritionally valuable foods you can eat while pregnant, as long as you choose lower-mercury options and cook them properly. The key is picking the right types and avoiding a short list of high-mercury fish.
Why Seafood Actually Helps During Pregnancy
Fish and shellfish are among the best dietary sources of omega-3 fatty acids, which play a direct role in your baby’s brain and vision development. These fats are especially important during the period around birth, when they support the formation of the protective coating around nerve fibers and help the visual system mature. A systematic review of eight clinical trials found that omega-3 supplementation during pregnancy improved measures of cognitive development in infants and children by 6% to 11% in five of the studies.
Seafood is also a natural source of iodine, a mineral your body uses to produce thyroid hormones. During pregnancy, those hormones regulate how your baby’s brain, bones, heart, and nervous system develop. A growing fetal brain needs the right level of thyroid hormones to form properly, and iodine deficiency can interfere with that process. Fish delivers iodine in a form your body absorbs easily, along with high-quality protein.
Which Fish to Avoid Completely
The concern with seafood during pregnancy comes down to mercury, a metal that accumulates in large, long-lived predatory fish. Mercury can cross the placenta and affect your baby’s developing nervous system. The FDA lists seven types of fish to avoid entirely during pregnancy because of their high mercury levels:
- Shark
- Swordfish
- King mackerel
- Marlin
- Orange roughy
- Tilefish (from the Gulf of Mexico)
- Bigeye tuna
These are all large predators that sit at the top of the food chain. Smaller fish and shellfish accumulate far less mercury and are safe to eat regularly.
How Much Seafood You Can Eat Per Week
The FDA divides safe fish into two tiers. “Best Choices” are the lowest-mercury options, and you can eat two to three servings per week. A serving is 4 ounces measured before cooking, roughly the size of the palm of your hand. This category includes salmon, shrimp, pollock, tilapia, cod, catfish, crab, and canned light tuna.
“Good Choices” contain moderate mercury levels. If you eat from this group, stick to one serving per week and skip other fish for the rest of that week. Albacore (white) tuna falls into this category. It typically contains about three times more mercury than canned light tuna, which is why the limits differ.
The Canned Tuna Question
Canned tuna is one of the most common sources of confusion. The type matters. Canned light tuna (usually skipjack) is a “Best Choice,” and two to three servings a week is fine. Canned white or albacore tuna has more mercury, so limit it to one serving per week with no other fish that week. If you’re someone who eats tuna sandwiches regularly, switching to canned light tuna is a simple way to stay well within safe limits.
Shellfish Is a Safe Option
Shrimp, crab, lobster, scallops, clams, oysters (cooked), and mussels are all low in mercury. They fall into the “Best Choices” category, so you can eat them two to three times a week. Because shellfish are small and low on the food chain, they don’t accumulate mercury the way large predatory fish do. They’re also good sources of protein and minerals.
Raw Fish, Sushi, and Smoked Seafood
The mercury question is separate from the food safety question. Even low-mercury fish can be risky if it’s raw or undercooked. During pregnancy, your immune system is slightly suppressed, which makes you more vulnerable to foodborne bacteria and parasites.
Raw sushi, sashimi, ceviche, and raw oysters all carry a risk of bacterial contamination that cooked seafood does not. While thorough freezing can kill parasites in fish, most medical guidance still recommends avoiding raw seafood entirely during pregnancy. In a survey of obstetricians, 82% said raw fish is not safe during pregnancy.
Refrigerated smoked seafood (like smoked salmon or lox) also poses a higher risk and is best avoided unless it’s been heated to a safe temperature. Canned or shelf-stable smoked seafood is fine.
How to Cook Seafood Safely
Cook finfish to an internal temperature of 145°F (63°C). At that point the flesh will look opaque and flake apart easily with a fork. You don’t necessarily need a thermometer for every piece of fish, but if you’re unsure, one removes all guesswork.
For shellfish, cook until the shells open on their own. Discard any that stay closed. Shrimp and lobster should be pearly white and opaque when done. Scallops should be milky white and firm.
The Bottom Line on Seafood and Pregnancy
Avoiding seafood entirely during pregnancy means missing out on nutrients that directly support your baby’s brain and nervous system development. The real risk isn’t seafood itself. It’s specific high-mercury species and raw or undercooked preparation. Stick to two to three servings a week of lower-mercury fish and shellfish, cook everything thoroughly, and skip the seven high-mercury species listed above. The FDA and EPA have not changed this guidance as of 2024, and a recent federal review concluded there isn’t enough evidence to revise the recommended amounts of seafood in dietary guidelines.