Expecting? Here’s Why Fish Still Belongs on Your Plate
Pregnancy comes with a flood of questions—diet, weight gain, supplements, exercise—and plenty of worries. One common concern is whether mercury in fish means you should skip seafood altogether. A large analysis published in JAMA Network Open offers reassuring news: when pregnant women eat fish in moderation, the benefits for their children outweigh the potential risks from mercury exposure.
What the Study Found About Fish, Mercury, and Kids’ Metabolic Health
Researchers analyzed data from 805 mother–child pairs in the HELIX project, which followed families in France, Greece, Norway, Spain, and the UK. Using food-frequency questionnaires during pregnancy and measuring mercury in maternal or cord blood, they examined how often mothers ate fish—categorized as less than once a week, one to three times a week, or more than three times a week—and tracked metabolic outcomes in the children between ages six and twelve.
Moderate fish intake—one to three servings weekly—was linked with a healthier metabolic profile in offspring. Children of mothers in the moderate and higher fish intakes also had lower levels of inflammatory markers (cytokines and adipokines), hinting that omega-3-rich seafood may dampen low-grade inflammation tied to metabolic syndrome. At the same time, higher prenatal mercury exposure was associated with less favorable metabolic scores, underscoring the need to choose lower-mercury species.
How Much Fish Is “Just Right” in Pregnancy?
The findings dovetail with U.S. FDA and EPA guidance: aim for eight to twelve ounces of a variety of low-mercury seafood per week during pregnancy and breastfeeding. That target works out to two to three modest servings and strikes a balance—enough EPA and DHA to support mom and baby without drifting into species more likely to carry higher mercury loads. Government resources categorize dozens of fish as “Best Choices” or “Good Choices,” including salmon, sardines, trout, anchovies, crab, grouper, halibut, and snapper, while advising against high-mercury fish such as shark and marlin.
Why Omega-3s Matter So Much for Moms and Babies
Seafood is the primary dietary source of the long-chain omega-3s EPA and DHA. These fats are anti-inflammatory and play critical roles in fetal brain and eye development. If fish isn’t on the menu often enough, a prenatal with DHA or a separate omega-3 supplement can help fill the gap. DHA from algae is a safe, fish-free option and is commonly used in prenatal products. Many experts recommend at least 200 mg of DHA per day in pregnancy; talk with your healthcare provider about the right amount for you.
Beyond Metabolism: Cognitive Benefits of Seafood Intake
Two comprehensive systematic reviews assembled for the 2020 Dietary Guidelines Advisory Committee found that seafood consumption during pregnancy is consistently associated with better neurocognitive outcomes in children compared with eating none at all. Benefits appeared even at low intakes—around four ounces a week—and persisted across higher intakes in the studies available. A separate review focusing on seafood eaten by children themselves reached similar conclusions for cognition and learning. Notably, these analyses did not identify net harms to neurodevelopment at the intake levels observed.
A Note on Study Design and What It Means for You
Like any observational research, the HELIX analysis can’t prove causation, and it relied on self-reported diet, which can be imperfect. The species of fish consumed weren’t tracked in detail. Even so, consistent patterns across countries—and the biological plausibility of omega-3s reducing inflammation—support the main takeaway: moderate, low-mercury seafood intake during pregnancy is a sensible, evidence-based choice.
DHA Supplementation: An Extra Layer of Protection
There’s growing evidence that prenatal DHA may deliver benefits that extend into childhood. In the KUDOS randomized, placebo-controlled trial, children who became overweight or obese had lower blood pressure if their mothers took DHA during pregnancy compared with placebo, suggesting a protective “programming” effect. Combined with the metabolic and cognitive data, this points to a simple strategy: pair smart fish choices with a reliable DHA source and check in with your clinician about your personal needs.
Putting It All Together
If you’re pregnant, you don’t need to avoid fish—you just need to choose wisely. Favor low-mercury, omega-3-rich seafood two to three times a week, consider a DHA-containing prenatal, and keep an eye on overall balance. The current science suggests that approach supports your health and offers your baby a head start on brain development and metabolic resilience.
