BiomaLearnFoodsNutrition factsNutrientsGuidesAnswersEvidence

Are sardines safe during pregnancy?

Cooked sardines, including canned ones, are among the safest fish to eat in pregnancy by the measure the US agencies use, which is mercury. FDA testing of 90 sardine samples found a mean of 0.013 ppm, against 0.126 ppm for canned light tuna and 0.73 ppm for king mackerel in the same FDA monitoring. FDA and EPA put sardines on their Best Choices list and advise 2 to 3 servings of 4 ounces a week for people who are pregnant or breastfeeding. We found no trial and no review of sardines on their own in pregnant women. Raw or marinated sardines are a separate matter, and the FDA says to avoid them.

Unsettled. Sardines themselves have never been tested in pregnancy for a health outcome. The benefit side of the answer comes from trials of omega-3 capsules and from cohorts of women eating fish of every kind. Sardines carry the same omega-3 fats, so the benefit is inferred, and inference is all it is.

Established. Omega-3 fats in pregnancy, given mostly as fish oil capsules in randomized trials, lowered preterm birth. In a Cochrane review, 11.9 percent of women on omega-3 gave birth before 37 weeks against 13.4 percent without it, across 26 trials and 10,304 women (RR 0.89, 95% CI 0.81 to 0.97). The review rated this high-quality evidence. It is evidence about the fats, and only by inference about the fish.

Preterm birth before 37 weeks, percent of women
0481216No omega-326 randomized trials, 10,304 women13.4No omega-3: 13.4 percent (95% CI 13.4 to 13.4)Omega-3, mostly capsulessame trials11.9Omega-3, mostly capsules: 11.9 percent (95% CI 11.9 to 11.9)

The absolute numbers behind the relative figure in the Cochrane review. The trials mostly gave fish oil capsules, so this describes omega-3 fats and not a serving of sardines. The review gives no interval for each arm, so none is drawn. Source: card ev-sardpg-01 below.

What the trials found

Omega-3 fats, in randomized trials

The Cochrane review behind the bars above also found fewer early preterm births, before 34 weeks: 2.7 percent against 4.6 percent, in 9 trials with 5,204 women (RR 0.58, 95% CI 0.44 to 0.77). The reviewers rated both results high quality. The trials mostly used fish oil capsules, and the card behind this page says so plainly.

Omega-3 and fish in pregnancy, on a risk scale
0.50.60.70.80.91.01.1no effectPreterm birth before 37 weeksomega-3, 26 trials, 10,304 womenPreterm birth before 37 weeks: 0.89 (95% CI 0.81 to 0.97)0.89Early preterm birth before 34 weeksomega-3, 9 trials, 5,204 womenEarly preterm birth before 34 weeks: 0.58 (95% CI 0.44 to 0.77)0.58Preterm birth, fish 1 to 3 times a week19 European cohorts, 151,880 pairsPreterm birth, fish 1 to 3 times a week: 0.87 (95% CI 0.82 to 0.92)0.87Preterm birth, fish 3 or more times a weeksame cohortsPreterm birth, fish 3 or more times a week: 0.89 (95% CI 0.84 to 0.96)0.89Food allergy in the child31 observational studiesFood allergy in the child: 0.75 (95% CI 0.64 to 0.88)0.75Wheeze in the childsame studiesWheeze in the child: 0.97 (95% CI 0.96 to 0.99)0.97
Randomized trialsObservational data

The top two rows are randomized trials, mostly of fish oil capsules. The lower four are observational and cover fish of every kind, with sardines never reported separately, so they show association and not cause. Sources: cards ev-sardpg-01, ev-sardpg-02 and ev-sardpg-06 below.

Fish of every kind, in cohorts

Pooled data from 19 European birth cohorts, 151,880 mothers and children, found that women eating fish more than once a week in pregnancy had a lower risk of preterm birth than women who rarely ate it. The adjusted risk ratio was 0.87 (95% CI 0.82 to 0.92) at one to three times a week and 0.89 (0.84 to 0.96) at three times or more. These are observational data, and sardines were not counted separately.

Two systematic reviews of observational studies, using US Dietary Guidelines methods, looked at seafood in pregnancy and the child's later development. They found no net harm to neurocognitive outcomes in children at the highest seafood intakes, even though mercury exposure rose with intake. A 2025 systematic review of 40 articles, almost all cohorts, linked seafood in pregnancy with better social-emotional and behavioral development. Its authors rated the certainty very low to moderate, because there are almost no randomized trials.

A meta-analysis of 31 observational studies linked more fish in pregnancy with less food allergy in the child (pooled effect 0.75, 95% CI 0.64 to 0.88) and slightly less wheeze (0.97, 95% CI 0.96 to 0.99). It covers fish of every kind.

The one study that fed sardines

In a small study that was not randomized, 15 healthy pregnant women ate sardines plus extra fish oil, 2.6 g of omega-3 fats a day for 9 weeks from week 26 to week 35, and 16 women did not. Their babies were born with 35.2 percent more DHA in their red blood cells and 45.5 percent more in plasma. DHA in the blood is a marker. The study did not measure birth outcomes or the child's development.

Who should be careful

Raw, cured and marinated sardines are the real caution. The FDA and the Dietary Guidelines say people who are pregnant should eat fish only when it has been cooked to a safe internal temperature. Canned sardines are heat processed, so this applies to raw dishes such as marinated or pickled fish. In 73 confirmed cases of anisakiasis in Italy, a parasitic infection from raw fish, raw or undercooked anchovies caused 65.7 percent. Anchovies or sardines were named in 15.1 percent and sardines alone in 1.4 percent. Those were cases in the general population, not in pregnancy.

Fish allergy can be severe. Among 81 fish-allergic patients in Spain, 42 percent had had anaphylaxis, and the average antibody level to sardine was 18.4 kUA/L. A raised antibody level is a sign of sensitization and does not by itself mean a reaction. If fish has caused you a reaction before, the advice to eat fish in pregnancy does not apply to you.

Mercury is what the US fish advice for pregnancy is built on, and on that measure sardines, at 0.013 ppm, are a tenth of canned light tuna. We found no pregnancy evidence on other contaminants in sardines, such as PCBs or dioxins, or on the salt in canned sardines.

Not for everyone. Eat sardines cooked or canned, never raw or marinated, while pregnant. If you have a fish allergy, sardines are fish, and the low mercury changes nothing about that.

What expert bodies say

FDA and EPA advise adults who are or might become pregnant, or are breastfeeding, to eat 2 to 3 servings a week of fish from the Best Choices category, a serving being four ounces, within a healthy diet. Sardines are on that list, with anchovies, salmon, trout and others. The advice is built on mercury. The FDA also says fish in pregnancy should be eaten only when cooked to a safe internal temperature.

EFSA, the European food safety authority, advises that toddlers, children and women of childbearing age get the benefits of fish by eating more of the species low in methylmercury. The statement names no species. By the FDA data above, sardines are a low one.

How we searched

Searched: a local copy of PubMed for sardines, oily fish, fish consumption and seafood with pregnancy, prenatal, maternal and gestation terms, which returned 471 records. A search for sardines alone returned 43, and only one of them fed sardines in pregnancy. We also searched the clinical trials registry (nothing), the retraction database (none of the included studies is retracted), the open web for EFSA advice and recent meta-analyses, and FDA and EFSA pages. Search run on 7 October 2026.

Included: the Cochrane review of omega-3 in pregnancy, a pooled analysis of 19 European cohorts, two systematic reviews of seafood and child development, a meta-analysis of fish and childhood allergy, the small sardine feeding study, an Italian case series on anisakiasis, the FDA mercury table, two FDA and EPA advice pages and an EFSA statement. Three cards already held in our base were added: one on fish allergy, the FDA Best Choices list naming sardines, and FDA mercury values for tuna and mackerel.

Excluded: a review of omega-3 capsules and childhood asthma, a smaller meta-analysis of three trials replaced by the Cochrane review, an older review replaced by the newer ones, an audit of Spanish fish guidelines and a scoping review of toxicants with no effect sizes, and a single case of arsenic poisoning that was not about pregnancy.

What we read: abstracts from PubMed, with each quotation checked against the abstract text, and the FDA and EFSA pages, each fetched twice.

What we could not get: the full texts of the Cochrane review and the European cohort analysis. Any statement from ACOG, RCOG or NICE naming sardines. NHS advice on oily fish in pregnancy, which sits outside our list of trusted sources. Pregnancy data on PCBs, dioxins, salt or vitamin A in sardines.

What would change this answer

More on sardines themselves, including calcium from the bones: Sardine.

The food behind this question

The same question for other foods (pregnancy)

Sources

  1. ev-sardpg-01 · Meta-analysis or systematic review · Cochrane systematic review and meta-analysis of randomized controlled trials · n = 10,304
    Preterm birth < 37 weeks (13.4% versus 11.9%; risk ratio (RR) 0.89, 95% confidence interval (CI) 0.81 to 0.97; 26 RCTs, 10,304 participants; high-quality evidence) and early preterm birth < 34 weeks (4.6% versus 2.7%; RR 0.58, 95% CI 0.44 to 0.77; 9 RCTs, 5204 participants; high-quality evidence) were both lower in women who received omega-3 LCPUFA compared with no omega-3.
    Who: 10,304 participants in 26 RCTs (preterm <37 wk) and 5,204 in 9 RCTs (early preterm <34 wk), omega-3 LCPUFA vs no omega-3
    Effect: preterm birth <37 wk RR 0.89 (95% CI 0.81 to 0.97); early preterm <34 wk RR 0.58 (0.44 to 0.77); high-quality evidence
    Certainty: Trials mostly used fish oil capsules, not sardines; sardines supply the same EPA and DHA, so the effect of the whole fish is inferred.
    Cochrane Database Syst Rev, 2018 · checked 2026-10-07 · we read the abstract
  2. ev-sardpg-02 · Observational data · meta-analysis of pooled harmonized individual data from prospective birth cohorts · n = 151,880
    Women who ate fish >1 time/wk during pregnancy had lower risk of preterm birth than did women who rarely ate fish (≤ 1 time/wk); the adjusted RR of fish intake >1 but <3 times/wk was 0.87 (95% CI: 0.82, 0.92), and for intake ≥ 3 times/wk, the adjusted RR was 0.89 (95% CI: 0.84, 0.96).
    Who: 151,880 mother-child pairs from 19 population-based European birth cohort studies
    Effect: preterm birth RR 0.87 (95% CI 0.82, 0.92) for >1 to <3 times/wk; RR 0.89 (0.84, 0.96) for >=3 times/wk vs <=1 time/wk
    Certainty: Observational; fish of all kinds, sardines not reported separately.
    Am J Clin Nutr, 2014 · checked 2026-10-07 · we read the abstract
  3. ev-sardpg-03 · Observational data · two systematic reviews of observational studies using Dietary Guidelines Advisory Committee methods · n = 106,237
    No net adverse neurocognitive outcomes were reported among offspring at the highest ranges of seafood intakes despite associated increases in mercury exposures.
    Who: 44 publications on 106,237 mother-offspring pairs and 25,960 children
    Effect: no net adverse neurocognitive outcomes in offspring at the highest seafood intakes, despite associated increases in mercury exposure
    Certainty: Observational studies; seafood of all kinds, sardines not reported separately.
    Prostaglandins Leukot Essent Fatty Acids, 2019 · checked 2026-10-07 · we read the abstract
  4. ev-sardpg-04 · Observational data · systematic review with GRADE, narrative synthesis · n = 40 articles
    The certainty of the evidence was very low to moderate due to the lack of RCTs.
    Who: 40 articles (1 RCT, 24 prospective cohorts, 1 retrospective cohort) on seafood intake in pregnancy and child outcomes
    Effect: better social-emotional, behavioral and aggregate development scores; inconsistent for overall cognition; no lactation studies
    Certainty: Very low to moderate certainty due to lack of RCTs; species not separated.
    Adv Nutr, 2025 · checked 2026-10-07 · we read the abstract
  5. ev-sardpg-05 · Observational data · non-randomized controlled comparison, 9 weeks, 2.6 g n-3 per day from sardines and fish oil · n = 31
    Fifteen healthy pregnant women were enrolled to receive a 9-wk dietary supplementation of n-3 fatty acids from the 26th to the 35th wk of pregnancy. Sixteen pregnant women were not supplemented and served as controls. n-3 Fatty acid supplementation consisted of sardines and additional fish oil, which provided a total of 2.6 g of n-3 fatty acids per day (d) for the 9-wk period of supplementation. ... In n-3-supplemented infants, DHA concentrations were 35.2% higher than in control infants in red blood cells and 45.5% higher in plasma.
    Who: Fifteen healthy pregnant women supplemented vs sixteen unsupplemented controls
    Effect: newborn DHA 35.2% higher in red blood cells and 45.5% higher in plasma
    Certainty: The only study found that fed sardines in pregnancy; not randomized; biomarker endpoint, not a clinical outcome.
    Lipids, 1996 · checked 2026-10-07 · we read the abstract
  6. ev-sardpg-06 · Observational data · systematic review and meta-analysis of observational studies · n = 31 studies
    Greater maternal fish intake was associated with a reduced risk of wheeze (Pooled effect size: 0.97; 95% CI: 0.96-0.99) and food allergy (0.75; 95% CI: 0.64-0.88).
    Who: 31 observational studies of maternal fish intake and offspring allergy
    Effect: food allergy 0.75 (95% CI 0.64-0.88); wheeze 0.97 (0.96-0.99)
    Certainty: Observational, fish of all kinds.
    Crit Rev Food Sci Nutr, 2022 · checked 2026-10-07 · we read the abstract
  7. ev-sardpg-07 · Position of an expert body · agency monitoring data table · n = 90
    SARDINE | 0.013 | 0.010 | 0.015 | ND | 0.083 | 90 | FDA 2002-2010
    Who: 90 sardine samples, FDA monitoring 2002-2010
    Effect: mean 0.013 ppm, median 0.010, max 0.083 ppm
    Certainty: US market samples, FDA 2002-2010.
    US FDA, Mercury Levels in Commercial Fish and Shellfish (1990-2012), content current as of 02/25/2022 · checked 2026-10-07 · we read the section
  8. ev-sardpg-08 · Position of an expert body · agency advice · n = —
    As an adult who is or might become pregnant or is breastfeeding, you should eat 2 to 3 servings a week of fish in the "Best Choices" category, based on a serving size of four ounces, in the context of a total healthy diet.
    Who: adults who are or might become pregnant or are breastfeeding
    Effect: 2 to 3 servings of 4 oz a week from Best Choices, which include sardines
    Certainty: Mercury-based advice; the list sentence on the page is phrased for children's higher intakes but names the Best Choices species.
    FDA/EPA, Questions and Answers on Advice about Eating Fish, content current as of 02/17/2022 · checked 2026-10-07 · we read the section
  9. ev-sardpg-09 · Position of an expert body · agency advice · n = —
    The Dietary Guidelines for Americans and FDA recommend that those who are pregnant and children should only eat foods with fish, meat, poultry, or eggs that have been cooked to safe internal temperatures to protect against microbes that might be in those foods.
    Who: people who are pregnant, and children
    Effect: only fish cooked to safe internal temperatures
    Certainty: Canned sardines are heat processed; the risk concerns raw, cured or marinated fish.
    FDA/EPA, Questions and Answers on Advice about Eating Fish, content current as of 02/17/2022 · checked 2026-10-07 · we read the section
  10. ev-sardpg-10 · Laboratory or animal data · retrospective case series from the literature · n = 73
    In most of the patients (65.7%), the source of infection was raw or undercooked anchovies, followed by "anchovies or sardines" (15.1%), generic "raw seafood" (15.1%), and sardines (1.4%).
    Who: 73 confirmed anisakiasis cases reported in Italy since 1996
    Effect: source: anchovies 65.7%, anchovies or sardines 15.1%, sardines 1.4%
    Certainty: General population, not pregnancy; supports the cooked-only advice for raw marinated small oily fish.
    Parasite, 2018 · checked 2026-10-07 · we read the abstract
  11. ev-sardpg-11 · Position of an expert body · agency scientific statement · n = —
    For toddlers, children and women of childbearing age, the benefits of eating fish should be met by increasing the consumption of species low in methylmercury.
    Who: toddlers, children and women of childbearing age
    Effect: choose species low in methylmercury
    Certainty: The statement names no species.
    EFSA, Fish: scenarios indicate benefits versus risks, news 22 January 2015 · checked 2026-10-07 · we read the section
  12. sard-r2-17 · Observational data · retrospective cohort · n = 81
    The study population comprised 81 patients (68% male)... 42% of patients experienced anaphylaxis. At T0, the average sIgE values were as follows: cod, 32.2 kUA/L; sardine, 18.4 kUA/L; hake, 17.5 kUA/L; salmon, 13.9 kUA/L; tuna, 4.5 kUA/L; and rGad c 1, 22.9 kUA/L.
    Who: 81 patients with fish allergy, 2005-2016
    Effect: mean sIgE sardine 18.4 kUA/L, cod 32.2, hake 17.5; anaphylaxis in 42%
    Certainty: Reactions mainly to hake and mackerel; sensitization to sardine does not equal a reaction.
    J Investig Allergol Clin Immunol, 2020 · checked 2026-09-29 · we read the abstract
  13. slt-r2-14 · Position of an expert body · agency advice · n = —
    As an adult who is or might become pregnant or is breastfeeding, you should eat 2 to 3 servings a week of fish in the "Best Choices" category, based on a serving size of four ounces, in the context of a total healthy diet. ... these fish are anchovies, Atlantic mackerel, catfish, clams, crab, crawfish, flounder, haddock, mullet, oysters, plaice, pollock, salmon, sardines, scallops, shad, shrimp, sole, squid, tilapia, trout, and whiting.
    Who: people who are or might become pregnant or are breastfeeding
    Effect: Best Choices, 2 to 3 servings of 4 oz a week
    Certainty: mercury-based advice, page content current as of 2024-03-05
    FDA/EPA, Questions and Answers on Advice about Eating Fish · checked 2026-10-02 · we read the section
  14. mvt-r3-11 · Position of an expert body · agency monitoring table · n = 80, 545, 21, 213 samples
    MACKEREL ATLANTIC (N.Atlantic) | 0.05 | N/A | N/A | 0.02 | 0.16 | 80 | NMFS REPORT 1978...TUNA (CANNED, LIGHT) | 0.126 | 0.077 | 0.134 | ND | 0.889 | 545 | FDA 1991-2010...TUNA (FRESH/FROZEN, BIGEYE) | 0.689 | 0.56 | 0.341 | 0.128 | 1.816 | 21 | FDA 1993-2005...MACKEREL KING | 0.73 | N/A | N/A | 0.23 | 1.67 | 213 | GULF OF MEXICO REPORT 2000
    Who: FDA and NMFS monitoring samples, US market
    Effect: 0.05 vs 0.126 vs 0.689 vs 0.73 ppm mean mercury
    Certainty: Mackerel rows come from 1978 and 2000 reports, tuna rows from FDA 1991-2010.
    FDA, Mercury Levels in Commercial Fish and Shellfish (1990-2012), content current 2022-02-25 · checked 2026-09-28 · we read the section

How this page was made. Evidence was extracted from primary sources into cards, every number was re-checked against the source, and the text was written from those cards. Bioma Learn has no human medical reviewer at this time, and we say so rather than invent one. Methodology. This is information, not medical advice.