Fish in pregnancy: Balancing Nutrients and Mercury Advice

Fish can contribute protein and other nutrients during pregnancy. Mercury advice is about choosing suitable species and amounts, rather than assuming every fish carries the same risk. The country where you receive care matters because serving guides and species lists differ.

Read the name on the label

Salmon, sardines, cod and other commonly available fish appear among lower mercury choices in US guidance. Tuna needs more detail: canned light tuna, albacore and bigeye are placed in different categories. “Tuna” alone may not give enough information to apply the advice.

Keep a photo of a product label if you want help identifying it. For a restaurant meal, ask which species is used. The same approach is useful for fish sold under a local name that you do not recognize in a national guide.

Use one local serving guide

UK guidance recommends two portions of fish weekly, including one oily fish portion, while limiting oily fish to two portions during pregnancy. A portion is around 140 grams cooked. It also limits tuna to two steaks or four medium cans weekly and says to avoid shark, swordfish and marlin. Tuna does not count as oily fish in this guidance.

US FDA and EPA advice uses four ounce portions measured before cooking. It recommends two or three weekly servings from its Best Choices list, or one serving from Good Choices with no other fish that week. Its avoid list includes bigeye tuna, king mackerel and several other species. These systems are alternatives, not allowances to add together.

Separate mercury from cooking safety

Cooking fish does not remove mercury from its flesh. Thorough cooking still matters because it addresses microbes that may be present. Choosing a lower mercury fish does not make raw sushi suitable during pregnancy. See the sushi guide for preparation questions.

If family or friends catch fish, check the advisory for that specific body of water. A general supermarket guide cannot account for every local contamination issue. Ask your local health or fisheries authority when there is no clear information.

Make a workable food plan

Vary the species you buy rather than relying on the same fish each time. If cost, allergy or preference means you do not eat fish, discuss alternative sources of its nutrients. The omega 3 guide explains why supplements and food are not interchangeable in every respect.

After one meal from a higher mercury category, focus on lower mercury choices going forward. Ask your clinician about repeated or unusual exposure rather than trying a detox product or deciding you need to avoid all fish.