Fish in Pregnancy: Low-Mercury, High Payoff

Is fish actually good for pregnancy?

Fish is one of the few foods that pregnancy guidance encourages eating more of, not less. Seafood supplies omega-3 fatty acids, especially DHA, which support fetal brain and eye development across the roughly 40 weeks of pregnancy, along with lean protein, iodine, and vitamin D. According to federal dietary advice, pregnant people who eat low-mercury fish may support neurodevelopment more than those who avoid fish entirely, which reframes the whole conversation. The worry many people carry, that all fish is risky, mixes up the small high-mercury list with the large low-mercury one. Prenatal nutrition leans on nutrient-dense foods, and low-mercury seafood fits that goal cleanly 1Ref 1Office on Women's Health (U.S. HHS) (2025).Prenatal care.Prenatal nutrition guidance encourages low-mercury seafood as a source of omega-3 fats, protein, and other nutrients in pregnancy.. The practical target most antenatal guidelines name is 8 to 12 ounces a week, roughly 2 to 3 servings 2Ref 2National Institute for Health and Care Excellence (2024).Antenatal care (NG201).Antenatal care includes dietary advice on eating fish in pregnancy while limiting high-mercury species..

Which fish are lowest in mercury?

Small, short-lived fish sit lowest in mercury and make up the best-choices list. Commonly recommended low-mercury options include:

• Salmon, sardines, anchovies, and herring
• Shrimp, scallops, crab, and other shellfish
• Canned light tuna, tilapia, cod, and pollock
• Trout, catfish, and Atlantic mackerel

The FDA and EPA best-choices chart lists dozens of species safe to eat 2 to 3 times a week. Albacore, or white, tuna and yellowfin tuna run higher, so guidelines suggest limiting them to about 1 serving a week. These low-mercury choices overlap with the cooked options that make sushi in pregnancy workable. Choosing variety across the low-mercury list also spreads out any trace exposures rather than concentrating them.

Which fish should be avoided in pregnancy?

A short list of large predator fish carries enough mercury to avoid during pregnancy. The FDA and EPA name shark, swordfish, king mackerel, Gulf tilefish, bigeye tuna, marlin, and orange roughy as fish to skip. These species live long and eat other fish, so methylmercury builds up in their tissue over years. High mercury exposure can affect a developing nervous system, which is the reason for the caution. Locally caught fish is a separate case: when no local advisory exists, guidance suggests limiting it to about 6 ounces, eaten within 7 days, and skipping other fish that week. This avoid list is far shorter than the low-mercury list, which is why the overall message about fish in pregnancy stays positive rather than fearful.

How do fish needs shift across pregnancy and nursing?

Fish stays valuable from the first trimester through breastfeeding, though appetite for it can rise and fall. Early on, in the first 12 weeks, nausea and food aversions may make fish smells hard to tolerate, and gentler, milder options like canned salmon or shrimp are easier then 3Ref 3American College of Obstetricians and Gynecologists (2018).ACOG Practice Bulletin No. 189: Nausea and Vomiting of Pregnancy.Nausea and food aversions of early pregnancy affect tolerance for fish, especially in the first trimester.. As nausea settles after about 14 weeks, many people find fish appealing again, and the omega-3 needs of the growing brain continue. During lactation, low-mercury fish remains encouraged because DHA passes into breast milk, while the same high-mercury species stay limited. Fatigue is common in pregnancy, and iron-rich seafood like sardines and canned salmon can support energy alongside prenatal vitamins. The through-line is that low-mercury fish helps at every stage.

When fish and mercury questions need a clinician

A history of high-mercury fish, a specific medical condition, or ongoing worry is worth raising with a clinician rather than guessing. An obstetric clinician can advise on how much fish fits your situation, review any concern about past mercury exposure, and confirm which local fish are safe. Most people, though, do well simply favoring the low-mercury list and staying within 2 to 3 servings a week. Nutrition questions have a natural home in routine prenatal care, and starting prenatal visits early opens that door. Gale can help you prepare those questions. An obstetric clinician or midwife can match the guidance to your health history.