Can You Eat Tuna When Pregnant?
Written by Jordan Morley · Reviewed against NHS foods-to-avoid guidance · Last updated 28 October 2026
Tuna is safe during pregnancy in limited amounts — no more than 2 tuna steaks or 4 medium cans a week, because of its mercury content.
Why is tuna a concern in pregnancy?
Tuna contains more mercury than most fish, and too much mercury can affect your baby's developing nervous system. The NHS advises limiting tuna to no more than 2 fresh tuna steaks (about 140g cooked each) or 4 medium-sized cans (about 140g drained each) per week during pregnancy. Within that limit, tuna is a healthy source of protein.
You can also check the calorie content of tuna alongside its safety information. Dog owners should check if tuna is safe for dogs before sharing, and cat owners can check whether cats can eat tuna.
The exception
Tuna has its own limit and does not count as oily fish: the NHS says fresh and canned tuna are not oily fish, so salmon, mackerel and sardines are counted separately. Raw tuna (sashimi, nigiri, a steak that is raw in the middle) is raw fish, which the NHS says to avoid even if it was frozen — see our sushi safety guide.
Tuna has its own limit, separate from oily fish
The most common mix-up on pregnancy fish pages is how tuna and oily fish count. The NHS fish page (last reviewed 26 June 2026) keeps them apart: 'Fresh and canned tuna do not count as oily fish.' That gives you two separate weekly allowances:
| Fish | Weekly limit in pregnancy | What counts as one | Source |
|---|---|---|---|
| Tinned tuna | No more than 4 cans | A medium can, drained weight about 140g | NHS; FSA blog |
| Fresh tuna steak | No more than 2 steaks | About 140g cooked (Tommy's: about 170g raw) | NHS; FSA blog; Tommy's |
| Oily fish (salmon, trout, mackerel, sardines, herring, pilchards, sprats) | No more than 2 portions | About 140g cooked | NHS fish page |
| Shark, swordfish, marlin | None: do not eat | n/a | NHS fish page |
So a week can include up to 4 cans of tuna and up to 2 portions of salmon or other oily fish, because the NHS counts them separately. nidirect says the same: tuna can be eaten in addition to the oily fish limit. The NHS gives the can limit and the steak limit separately and does not say how to combine them, so if you eat both in the same week, stay comfortably under each and ask your midwife if tuna is a daily habit. That last point is our judgement.
A worked week
| Day | Meal | Counts as |
|---|---|---|
| Monday | Tuna mayo sandwich (one medium can, about 140g drained) | 1 of 4 cans |
| Tuesday | Salmon fillet, about 140g cooked | 1 of 2 oily fish portions |
| Wednesday | Tuna and sweetcorn pasta (one medium can) | 2 of 4 cans |
| Friday | Tuna melt (one medium can) | 3 of 4 cans |
| Saturday | Grilled mackerel, about 140g cooked | 2 of 2 oily fish portions |
| Sunday | Tuna salad (one medium can) | 4 of 4 cans: at the limit, stop here |
Small cans are not automatically 'half a can': check the drained weight on the label and compare it with the 140g the FSA uses for a medium can.
Why the limit exists, in the FSA's words
A Food Standards Agency blog (27 November 2024) explains that mercury occurs naturally in all fish and cannot be removed entirely. Predatory fish like tuna have more, because it builds up from the fish they eat, and 'an older, larger fish is likely to have higher levels of mercury'. The FSA wrote the post in response to a study by Bloom that tested 148 tins, all of which contained some mercury; only a relatively small number exceeded the legal maximum, which in Great Britain is 1.0 mg/kg for tuna. The FSA said it has 'no evidence that tinned tuna is unsafe to eat' and that pregnant women and those trying for a baby should keep to the NHS limits.
Fresh tuna steak: raw, seared and sushi
The weekly steak limit is about mercury. Raw tuna is a separate listeria and food-poisoning question: the NHS lists raw fish as a food to avoid, including sushi made with raw fish even if it was frozen first. That means tuna sashimi, nigiri and poke are out, and a steak seared on the outside but still raw in the middle is, in our reading, raw fish too. Cook a steak through in pregnancy. See sushi in pregnancy for a type-by-type table.
What other pages say
Mother & Baby's tuna article (about 700 words) gives the 2-steak and 4-can limits and says fresh tuna is better than canned because canned has fewer omega-3 fatty acids; we did not find a source for that on the page, so we have not repeated it. Huggies UK gives the same limits with the 170g raw / 140g drained sizes. Neither page says that tuna sits outside the oily fish limit, or that raw and rare tuna are a different issue.
Sources checked
Everything in the sections above was checked against these pages on 28 October 2026.
- NHS: Fish and shellfish (page last reviewed 26 June 2026) — tuna: 4 cans or 2 steaks in pregnancy; fresh and canned tuna do not count as oily fish; oily fish 2 portions; shark, swordfish, marlin avoid; no tuna limit when breastfeeding; reviewed 26 June 2026
- NHS: Foods to avoid in pregnancy (page last reviewed 15 June 2026) — tuna limit; raw fish and sushi with raw fish avoid even if frozen; last reviewed 15 June 2026
- Food Standards Agency blog: Should we be concerned about mercury in tinned tuna? (27 November 2024) — mercury in fish; medium can about 140g drained; 140g cooked steak; legal maximum 1.0 mg/kg; no evidence tinned tuna is unsafe
- nidirect (Northern Ireland government): Foods to avoid in pregnancy (modified 3 April 2025) — tuna can be eaten in addition to the oily fish limit
- Tommy's: Foods to avoid in pregnancy (last reviewed 6 September 2024) — tuna steak about 140g cooked or 170g raw
- Mother & Baby: Is it safe to eat tuna during pregnancy? — rival: limits and omega-3 claim (not repeated)
- Huggies UK: Foods to avoid when pregnant (27 May 2024) — rival: 2 steaks (170g raw) or 4 medium cans (140g drained)
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Pregnancy essentials
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Check Price →Tuna: the other answers on this site
| Question | Short answer (links to the full page) |
|---|---|
| While breastfeeding | No limit per NHS, but two NHS pages differ on fresh tuna |
Common questions
Can I eat tuna in the first trimester?
Yes — the same weekly tuna limit applies throughout pregnancy, including the first trimester.
Is a small amount of tuna OK during pregnancy?
Yes — within the limit of 2 steaks or 4 medium cans per week, tuna is considered safe.
I accidentally ate tuna while pregnant — what should I do?
Going over the limit in a single week is not a cause for panic — the limit protects against gradual mercury build-up. Simply return to within the limit going forward.
Is cooked tuna safe in pregnancy?
Cooking doesn't change tuna's mercury content, so the same limits apply. Raw tuna, for example in sushi, is on the NHS list of foods to avoid even if it has been frozen first.
Does tuna count as oily fish in pregnancy?
No. The NHS says 'Fresh and canned tuna do not count as oily fish.' Tuna has its own limit (4 cans or 2 steaks a week), and the oily fish limit of 2 portions a week applies to fish like salmon, mackerel and sardines.
Can I eat tuna and salmon in the same week?
Yes. They count separately: up to 4 medium cans (or 2 steaks) of tuna and up to 2 portions of oily fish such as salmon.
How big is a can of tuna for the 4-can limit?
The FSA says the NHS limit is based on a medium can with a drained weight of about 140g. Check the drained weight on smaller or larger cans.
Can I eat tuna sushi or a rare tuna steak when pregnant?
No. The NHS lists raw fish as a food to avoid, even if it was frozen, so tuna sashimi, nigiri and rare-in-the-middle steaks are out. Cooked tuna is fine within the weekly limits.
Is tuna safe while breastfeeding?
The NHS says that if you are breastfeeding there is no limit on how much tuna you can eat. See <a href='/can-you-eat-tuna-when-breastfeeding/'>tuna when breastfeeding</a>.
Related answers
Primary source: NHS foods-to-avoid guidance.
General information only, not medical advice: see the medical disclaimer. Feeling unwell after eating something? Contact NHS 111 or your GP.