Is edamame safe during pregnancy?

As an ordinary food, nothing we found says it is not. No study has tested edamame itself in pregnant women, and no review has pooled soy foods and fetal safety. The evidence that exists is about soy foods and soy isoflavones in general. The US National Center for Complementary and Integrative Health says soy in pregnancy may be unsafe only in amounts greater than those commonly found in foods. In Japan, among 41,578 mothers of baby boys, the highest isoflavone intake in early pregnancy was not linked to hypospadias (OR 0.9, 95% CI 0.4 to 2.4), from 51 cases in total.

Unsettled. This is a safety answer built from soy in general and from observational data. A cohort can show that women who ate more soy did not fare worse. It cannot prove that soy caused nothing, and no trial has given pregnant women edamame and watched what happened.

What the trials found

The one randomized trial in pregnancy

In a randomized trial of 68 women in Iran with gestational diabetes, a 6-week diet that took 35 percent of its protein from soy lowered fasting glucose by 12.7 mg/dL, while it rose by 1.4 mg/dL on the control diet. Newborn jaundice was less common in the soy group, 8.8 percent against 32.4 percent. That is one small trial, in women who already had gestational diabetes, and the soy foods were not named as edamame.

The large pregnancy cohorts

In the Japan Environment and Children's Study of 84,948 pregnant women, those with the highest soy isoflavone intake had an 18 percent lower risk of gestational diabetes than those with the lowest (RR 0.82, 95% CI 0.70 to 0.95). In a Chinese cohort of 1495 women the highest third of soy food intake was linked to a 27 percent lower risk against no soy, with an interval that almost touches no effect (0.54 to 0.99). These are relative figures, and the abstracts do not give the absolute rates behind them. In 2418 Chinese women the highest isoflavone intake went with lower odds of severe pregnancy vomiting (OR 0.56), in a cross-sectional analysis where the sickness itself may have cut how much soy women ate.

Thyroid, the worry people raise most

A meta-analysis of 18 randomized trials found soy did not change the thyroid hormones fT3 or fT4 and raised TSH by 0.25 mIU/L, a rise its authors call of unclear clinical meaning. Those trials were not in pregnant women. In a 10-week trial of 63 healthy young women eating soy foods, with about 19 g of soy protein and 36 mg of isoflavones a day, TSH and free thyroxine did not move and iron status did not change. Thyroid was a secondary outcome there, and iodine intake was not reported.

Who should be careful

Not for everyone. Soy allergy is the clear exception. A 2023 meta-analysis of 93 European studies put soy allergy confirmed by food challenge at 0.3 percent of people, and self-reported lifetime allergy at 0.5 percent. Edamame is the whole soybean, and nothing suggests it is less allergenic than other soy foods. In the United States soy must be declared on the label of packaged foods.

The NIH caution is about amounts beyond food, such as isoflavone supplements and concentrates, and it gives no number for where that line falls. If you have a thyroid condition, the trials above did not include pregnant women or people with thyroid disease, so how soy fits with your treatment is a question for whoever manages it.

The Japanese data on food allergy in children show no sign of harm. In 86,012 mother-child pairs, higher isoflavone intake in pregnancy went with slightly lower odds of food allergy by age 1 (aOR 0.86, 95% CI 0.79 to 0.93), as reported by parents.

What edamame brings

Folate is where edamame earns its place in a pregnancy diet. In the USDA survey database cooked edamame has 286 mcg of folate per 3.5 oz (100 g), about 458 mcg in a 160 g cup. Pregnancy raises the recommended folate intake from 400 to 600 mcg DFE a day. The database figure is total food folate and the requirement is in dietary folate equivalents, so treat the comparison as rough. This is folate from food, not the folic acid in supplements, and this page does not cover supplements. Whether you need one in pregnancy is a question for your doctor or midwife. USDA analysis of 4 samples of frozen prepared edamame found less, 185 mcg per 3.5 oz (100 g), ranging from 127 to 255. Boiling and draining loses folate into the water. For vegetables in general, cooking from frozen and draining keeps 55 percent, and boiling in little water keeps 65 to 70 percent. Those factors were measured on vegetable groups, not on edamame itself.

What expert bodies say

The US National Center for Complementary and Integrative Health separates food from supplements. Soy in pregnancy may be unsafe only in amounts greater than those commonly found in foods. We found reports that the French food safety agency set a lower isoflavone reference value for pregnant women in 2025, and could not reach the agency's own document, so it is not used here. More on the bean itself is on the edamame page, and on the nutrient in the folate guide.

How we searched

What would change this answer

• A systematic review of soy food or isoflavone intake in pregnancy and outcomes in the baby, such as hypospadias, undescended testes and birth weight. We found none.
• A primary document from ANSES or the European Food Safety Authority on isoflavones in pregnancy. If European bodies are more cautious than the NIH, this page would report both.
• Any trial of edamame itself in pregnant women. None was registered when we searched.

Sources

1. ev-edp-01 · Observational data · prospective birth cohort · n = 84948
   Compared with those in the lowest quintile of soy isoflavone intake, women in the highest quintile were found to have experienced a significantly lower risk of GDM (multivariate relative risk = 0.82; 95% confidence interval: 0.70, 0.95; P for trend = 0.05).
   
   Who: Japanese pregnant women (median gestational age 12 weeks), diet in the 12 months before enrollment by food frequency questionnaire
   Effect: RR 0.82 (0.70-0.95) highest vs lowest quintile of soy isoflavone intake; P for trend = 0.05
   Certainty: Observational data; edamame was not analyzed separately, association with miso and natto, tofu is nonlinear.
   Eur J Nutr, 2021 · checked 2026-10-07 · we read the abstract
2. ev-edp-02 · Randomized controlled trial(s) · randomized controlled trial · n = 68
   Compared with soy protein consumption, the control group significantly increased fasting plasma glucose (+1.4 ± 11.6 vs -12.7 ± 13.2 mg/dL, P < .001), serum insulin levels (+5.0 ± 11.6 vs -0.9 ± 10.0 μIU/mL, P = .02), homeostasis model of assessment-insulin resistance (+1.2 ± 2.7 vs -0.8 ± 2.2, P = .002), and decreased quantitative insulin sensitivity check index (-0.007 ± 0.02 vs +0.01 ± 0.03, P = .004).
   
   Who: women with gestational diabetes, control diet (0.8 g/kg protein, 70% animal) vs soy diet (35% animal, 35% soy, 30% other plant protein) for 6 weeks
   Effect: fasting plasma glucose +1.4 ± 11.6 vs -12.7 ± 13.2 mg/dL (P < .001); newborn hyperbilirubinemia 32.4% vs 8.8% favoring soy
   Certainty: A single small RCT from Iran; the soy protein is not specified by food; no edamame separately.
   J Clin Endocrinol Metab, 2015 · checked 2026-10-07 · we read the abstract
3. ev-edp-03 · Observational data · prospective birth cohort · n = 41578
   Adverse or beneficial effects of genistein on hypospadias were not observed in the high intake group (≥90th percentile) (OR = 0.9, 95% confidence interval = 0.4-2.4).
   
   Who: mothers in a nationwide Japanese birth cohort who delivered singleton live male births, genistein intake by food frequency questionnaire in early pregnancy
   Effect: high intake (>=90th percentile) OR 0.9 (0.4-2.4); low intake (<=10th percentile) OR 2.8 (1.4-5.8); median genistein 15.3 mg/day; 51 cases
   Certainty: 51 cases; the high dose here is a dietary Japanese one, not supplements.
   Urology, 2019 · checked 2026-10-07 · we read the abstract
4. ev-edp-04 · Observational data · prospective cohort · n = 1495
   Our study found that, compared with the non-consumers, the highest tertile of soy foods intake was associated with a decrease in risk of GDM (RR = 0.73, 95%CI: 0.54-0.99, p = .049).
   
   Who: pregnant women in Southwest China, 3-day 24-h dietary recalls at 6-14 weeks, OGTT at 24-28 weeks
   Effect: RR 0.73 (0.54-0.99) highest tertile vs non-consumers; median soy food intake 2.9 g/d
   Certainty: Observational data; intake is low, CI near 1.
   J Matern Fetal Neonatal Med, 2022 · checked 2026-10-07 · we read the abstract
5. ev-edp-05 · Observational data · cross-sectional analysis within a birth cohort · n = 2418
   After full adjustment for confounding factors, the results indicated that individuals with the highest dietary intake of soy isoflavones had a lower risk of developing HG (OR: 0.56, 95% CI: 0.36, 0.88. Ptrend = 0.012).
   
   Who: Chinese pregnant women, 108-item food frequency questionnaire
   Effect: OR 0.56 (0.36-0.88) highest vs lowest intake; median isoflavone intake 14.56 mg/d
   Certainty: Cross-sectional analysis: reverse causation possible (nausea reduces intake).
   Nutrients, 2025 · checked 2026-10-07 · we read the abstract
6. ev-edp-06 · Observational data · prospective birth cohort · n = 86012
   Maternal ISO consumption was negatively associated with FA in all children aged ≤1 year (Q3, adjusted odds ratio [aOR]: 0.91, 95% confidence interval [CI]: 0.84-0.99; Q4, aOR: 0.86, 95% CI: 0.79-0.93) and in those aged 1-3 years (Q3, aOR: 0.93, 95% CI: 0.88-0.99; Q4, aOR: 0.88, 95% CI: 0.83-0.95).
   
   Who: mother-child pairs in the Japan Environment and Children's Study, maternal isoflavone intake by food frequency questionnaire
   Effect: food allergy at <=1 year: Q4 vs Q1 aOR 0.86 (0.79-0.93); at 1-3 years aOR 0.88 (0.83-0.95)
   Certainty: Observational data; allergy was reported by parents.
   Pediatr Allergy Immunol, 2026 · checked 2026-10-07 · we read the abstract
7. ev-edp-07 · Meta-analysis or systematic review · systematic review and meta-analysis of RCTs · n = 18 articles
   Soy supplementation has no effect on the thyroid hormones and only very modestly raises TSH levels, the clinical significance, if any, of the rise in TSH is unclear.
   
   Who: randomized controlled trials with soy as intervention measuring fT3, fT4 and TSH (not pregnancy-specific)
   Effect: fT3 WMD 0.027 pmol/L (-0.052 to 0.107); fT4 WMD -0.003 pmol/L (-0.018 to 0.011); TSH WMD +0.248 mIU/L (0.001-0.494)
   Certainty: Non-pregnant adults; for pregnant women with hypothyroidism, separating soy and levothyroxine in time matters more (not studied separately here).
   Sci Rep, 2019 · checked 2026-10-07 · we read the abstract
8. ev-edp-08 · Meta-analysis or systematic review · systematic review and meta-analysis · n = 93 studies
   The point prevalence of food challenge-verified allergy were as follows: cow's milk (0.3%, 0.1-0.5), egg (0.8%, 0.5-1.2), wheat (0.1%, 0.01-0.2), soy (0.3%, 0.1-0.4), peanut (0.1%, 0.0-0.2), tree nuts (0.04%, 0.02-0.1), fish (0.02%, 0.0-0.1) and shellfish (0.1%, 0.0-0.2).
   
   Who: European studies of the eight big food allergens, all age groups, published up to 2021
   Effect: soy: self-reported lifetime 0.5% (0.3-0.7); challenge-verified point prevalence 0.3% (0.1-0.4)
   Certainty: Not about pregnant women; edamame is a whole soybean, allergenic in the same way as other soy products.
   Allergy, 2023 · checked 2026-10-07 · we read the abstract
9. ev-edp-09 · Position of an expert body · government consumer page
   The use of soy during pregnancy may be unsafe in amounts greater than those commonly found in foods.
   
   Who: pregnant women
   Effect: food amounts not flagged; amounts above food levels (supplements, concentrated isoflavones) may be unsafe
   Certainty: Position without its own analysis; distinguishes food from supplements, no numeric limit.
   NIH NCCIH, Soy: Usefulness and Safety (updated April 2025) · checked 2026-10-07 · we read the section
10. ev-edp-10 · Position of an expert body · government consumer page
    Some people are allergic to soy. In the United States, the presence of soy in packaged foods and dietary supplements must be indicated on the product label.
    
    Who: general population
    Effect: soy allergy exists; mandatory soy labeling in US packaged foods and supplements
    Certainty: Position without its own analysis.
    NIH NCCIH, Soy: Usefulness and Safety (updated April 2025) · checked 2026-10-07 · we read the section
11. ev-edp-11 · Position of an expert body · government fact sheet
    To meet this need, the FNB increased the folate RDA from 400 mcg DFE/day for nonpregnant women to 600 mcg DFE/day during pregnancy [2].
    
    Who: pregnant women
    Effect: RDA 600 mcg DFE/day in pregnancy vs 400 mcg DFE/day non-pregnant
    Certainty: Norm; edamame as a folate source is from the dataset card below.
    NIH Office of Dietary Supplements, Folate Fact Sheet for Health Professionals · checked 2026-10-07 · we read the section
12. ev-edp-12 · Position of an expert body · dataset
    FNDDS 41420020 Edamame, cooked (fdc_id 2707436): Folate, total 286 mcg/100 g, 1 cup 160 g 457.6 mcg, Quantity not specified 80 g 228.8 mcg
    
    Who: US dietary survey food code
    Effect: folate, total 286 mcg/100 g; 1 cup 160 g 457.6 mcg; quantity not specified 80 g 228.8 mcg
    Certainty: Serving converted from 100 g; food folate, not folic acid, and not DFE.
    USDA FNDDS 2021-2023, food code 41420020, Edamame, cooked (fdc_id 2707436) · checked 2026-10-07 · we read the dataset
13. ev-edp-13 · Position of an expert body · dataset · n = 4
    Edamame, frozen, prepared | Folate, total 185.3 ug per 100 g (range 126.6-255.0, median 179.9, n=4)
    
    Who: US retail samples of frozen edamame, prepared
    Effect: folate, total 185.3 mcg/100 g (range 126.6-255.0, median 179.9)
    Certainty: 4 samples; spread 69%.
    USDA FoodData Central, Foundation Foods (release 2026-04-30), Edamame, frozen, prepared · checked 2026-10-07 · we read the dataset
14. eda-p1-02 · Randomized controlled trial(s) · randomized controlled trial over 10 weeks with blood and urine samples and 3-day dietary records at baseline and after the intervention, testing two to three servings of soy foods a day against animal foods · n = 63
    After intervention, no significant changes were observed in hemoglobin, transferrin saturation, serum iron, ferritin, or transferrin receptor (TFR) concentrations.
    
    Who: non-smoking women aged 18 to 28 without chronic disease, anemia, pregnancy or irregular menstrual cycles, randomized to soy food (n=31) or animal food (n=32)
    Effect: the soy diet supplied about 19 g protein and about 36 mg isoflavones a day; after the intervention there was no significant change in hemoglobin, transferrin saturation, serum iron, ferritin or transferrin receptor, and plasma zinc fell equally in both groups by 0.8 micromol/L
    Certainty: 63 young healthy women over 10 weeks is small and short for an iron-status endpoint, and everyone started with normal status, so this cannot speak to people who are already deficient. Plasma zinc fell in the animal-food arm too, which is what makes it uninformative about soy. Full text not retrievable (publication to the local PMC store blocked, see module docstring)
    Journal of Women's Health, 2011 · checked 2026-09-22 · we read the abstract
15. eda-p1-03 · Randomized controlled trial(s) · secondary outcomes of the same 10-week randomized controlled trial, measuring thyroid-stimulating hormone and free thyroxine alongside bone markers · n = 63
    No significant changes were observed in bone resorption, thyroid-stimulating hormone (TSH), or free thyroxine after soy food intake.
    
    Who: the same 63 premenopausal women, 31 on soy foods and 32 on animal foods
    Effect: no significant changes in thyroid-stimulating hormone or free thyroxine after soy food intake, at about 19 g soy protein and about 36 mg isoflavones a day for 10 weeks
    Certainty: these were secondary outcomes in a trial powered for mineral status, so an absence of change here is weaker than a trial designed to look for it. All the women were healthy with no stated thyroid disease and iodine intake was not reported, and the concern in the literature concentrates on people who are iodine deficient or already hypothyroid, whom this trial did not include
    Journal of Women's Health, 2011 · checked 2026-09-22 · we read the abstract
16. eda-p1-11 · Position of an expert body · USDA Table of Nutrient Retention Factors Release 6 (2007), the group-level rows for Vegetables and Vegetable Products (group 11) that apply to any food in the group, read for folate · n = 25 method rows
    folate_total_ug · group 11 Vegetables and Vegetable Products · 3019 VEG,GREENS,COOKED FROM FROZEN,DRAIN, 55% · 3005 VEG,GREENS,BOILED,WATER COVER DRAIN, 60% · 3004 VEG,GREENS,BOILD,LITTLE WATER DRAIN, 65% · 3774 VEG,OTHER,BLD,LITTLE WATER,DRAINED, 70%
    
    Who: group 11, Vegetables and Vegetable Products; 25 method rows carry a folate factor
    Effect: cooked from frozen and drained retains 55% of folate, boiled under a cover of water and drained 60%, boiled in little water and drained 65%, and boiled in little water as other vegetables 70%
    Certainty: the table is written on food GROUPS, not on edamame, so this is the factor for vegetables and greens applied to it, and the page must say so in those words. The spread from 55% to 70% is the whole practical point: the loss is leaching into water that gets poured away, which is why edamame steamed or boiled in the pod loses less than the same beans boiled loose and drained. Protein does not appear in Release 6 at all, among its 26 nutrients, so the table says nothing about protein losses either way
    USDA Table of Nutrient Retention Factors, Release 6 (2007) · checked 2026-09-22 · we read the dataset