Tuna can be part of a healthy pregnancy diet, but the amount and type matter because of mercury. The FDA, NHS, and ACOG all say pregnant people can eat tuna, just within specific weekly limits. Canned light tuna is lower in mercury than albacore ("white") or fresh tuna steaks, so the guidance differs by type.
Tuna is a popular, protein-rich fish that also provides omega-3 fatty acids, which support your baby's brain and eye development. The catch is mercury. Tuna, especially larger and older fish, can accumulate methylmercury, which the FDA and EPA note can affect a developing baby's nervous system. That is why tuna sits in the "eat, but limit" category rather than being fully unrestricted or fully off-limits.
The FDA and EPA place canned light tuna in their "Best Choices" list and say pregnant people can have 2 to 3 servings (about 8 to 12 ounces) of low-mercury fish per week. Albacore or "white" tuna and yellowfin are higher in mercury, so the FDA advises limiting these to one serving (about 4 ounces) per week. The NHS similarly advises no more than two tuna steaks or four medium cans of tuna per week. Bigeye tuna, often used in sushi and steaks, is on the FDA's "Choices to Avoid" list and should be skipped during pregnancy.
Check which tuna you are eating: canned light is the safer everyday choice, while albacore, yellowfin, and fresh steaks count toward stricter limits. Raw tuna in sushi or sashimi carries an added risk of listeria and parasites, so the NHS and FDA advise cooking fish thoroughly during pregnancy. If you want the omega-3 benefits with less mercury worry, the FDA's "Best Choices" include salmon, sardines, cod, tilapia, and shrimp. Spreading fish across the week rather than eating a lot at once also helps you stay within limits.