Study: Eating fish during pregnancy protects against mercury toxicity

Really Safe to eat fish during pregnancy? You may have been told to avoid them, to eat only limited amounts or certain types, but a recent study suggests that these restrictions may not be necessary.

The study in Neurotoxicology find that It is unlikely that mercury levels in fish will have a negative effect on your child if you eat fish, which suggests that eating fish can be protective against exposure to mercury.

For the most part, current advice on Mercury toxicity during pregnancy Pregnant women are warned against eating certain types of fish that are known to contain high levels of the mineral. The US Food and Drug Administration (FDA) tells expectant mothers to avoid eating large fish including swordfish, bigeye tuna, mackerel and certain other types of fish.

But guidelines can be confusing, as other organizations continue to promote fish consumption during pregnancy: Scientific Advisory Committee on Dietary Guidelines 2020-2025 for Americans publicly acknowledge Fish have “mostly beneficial associations” and “few harmful associations”.

An analysis of more than 4,131 pregnant mothers who had mercury in their bodies showed that it did not cause harmful effects on their babies – as long as the mother ate the fish.

If she does not eat fish, there is some evidence that her level of mercury can have a harmful effect on the baby. This may be due to the benefits from the combination of essential nutrients that fish provides, including long-chain fatty acids, iodine, vitamin D, and selenium.” Caroline Taylor, of the study and a senior research fellow at the University of Bristol Medical School, University of Bristol.

Jan Golding, Ph.D.Co-author and Professor Emeritus at the University of Bristol, told Motherly, she was fascinated by the strong protective effect of harmful effects when mercury comes from fish. But she was not surprised that eating fish during pregnancy was beneficial for the baby.

Related: Study finds heavy metals abound in homemade baby food too

Should fish be avoided during pregnancy?

Worried that some fish still need to stay off the menu while waiting for your bundle of joy to arrive? The researchers say that the types of fish the women ate didn’t seem to matter – the nutrients in the fish could protect the mother from the mercury content.

Other studies They explored the topic (many say fish are totally OK), but this study was unique in that it looked at populations with contrasting mercury levels, then followed up on children during childhood. One population group was in the Seychelles off East Africa, where most pregnant women eat fish regularly, and prenatal mercury levels are More than 10 times the amount seen in the United States. The second study used data from a population in England, where fish is not common in prenatal diets. The researchers found that increased levels of mercury were not associated with negative outcomes for children born to mothers who ate fish.

We know there are benefits to eating fish during pregnancy – that is, omega-3 fatty acids can promote brain and eye development. But the warnings issued prompted some women to avoid fish completely during pregnancy.

Related: The scientific reason why pregnant women create a ‘bubble from space’ around themselves

New guidelines for fish during pregnancy on the road?

That’s why the advice should be changed, says Dr. Golding.

Dr Golding says: “It is important that advice from health professionals review their advice against eating certain types of fish. There is no evidence of harm from these fish, but there is evidence from different countries that such advice can cause confusion in women. pregnant women.”

Dr. Golding says the guidelines should advise women to eat at least two servings of fish each week — and one of them should be oily fish Like salmon or albacore tuna.

Pregnant women should not eat raw fish or seafood, notes Asima Ahmed, MD, reproductive endocrinologist, obstetrician-gynecologist and co-founder of carrot fertility. “This is to avoid exposure to certain bacteria and parasites, including listeria,” she notes.

Related: Is it safe to eat sushi during pregnancy?

Dr. Ahmed, who was not involved in the research, says there are still many options a pregnant woman can eat. Safe fish to eat during pregnancy They include salmon, albacore tuna, mackerel, anchovies, cod, and trout, to name a few.

“Although there is cautionary advice against certain types of fish, there is no evidence to support any adverse effects,” says Dr. Golding.

Dr. Golding hopes the study results will influence the way public recommendations are written.

“They should promote the positive effects without any misleading caveats,” she says. “Ignore all warnings that you should not eat certain fish.”

Because the world tends to follow what the United States does with medical recommendations, Dr. Golding hopes that America will take the lead.

But Dr. Ahmed tells Motherly she doesn’t think this study will be enough to change the guidance.

“I think if similar studies were completed in different regions of the world with different populations, yet continued to have the same results, there is a greater possibility that the recommendations might change,” says Dr. Ahmed.

In the meantime, don’t get discouraged or get caught up in conflicting information. Women should not think that they should continue to limit or avoid seafood during pregnancy because the study is just another source of “inconsistency and endless confusion on this general topic,” Phil Spiller, former director of the Food and Drug Administration’s Office of Seafood, says my mother. (He was not affiliated with the study).

“Dr. Golding’s analysis and the conclusions that she and her colleagues have provided are the real deal and pregnant women and their health care providers should understand this,” he adds.


Golding J, et al. Benefits of eating fish: findings on prenatal exposure to mercury and outcomes for children from the ALSPAC antenatal group. Neurotoxicology. 2022.

Simon M et al. Maternal consumption of fish during pregnancy is associated with A bifidobacteriumThe dominant microbiome in infants. 2020. Current Developments in Nutrition.

Snetselaar L, et al. Seafood consumption during pregnancy and lactation and child neurodevelopment: a systematic review. Systematic review of USDA nutrition guides. 2020.

Featured Experts

Caroline TaylorHe holds a Ph.D. and is a Senior Research Fellow at the University of Bristol Medical School, Bristol

Jane GoldingPh.D., is Professor Emeritus at the University of Bristol

Phil Spiller He is the former director of the Food and Drug Administration’s Office of Seafood

Asimah Ahmed, obstetrician and gynecologist, reproductive endocrinologist and co-founder of carrot fertility.