Is Seaweed Safe During Pregnancy? (Updated 2026 Guide)
Updated March 22, 2026
The Answer
With caution. Seaweed is nutritious but requires moderation during pregnancy due to its high iodine content, which can affect your baby's thyroid development if consumed in excess.
Seaweed is rich in vitamins, minerals, and omega-3 fatty acids that benefit pregnancy, but the primary concern is excessive iodine intake. Too much iodine can cause transient or permanent congenital hypothyroidism in newborns, potentially impairing neurodevelopment. Some seaweed products also contain elevated levels of inorganic arsenic, making moderation essential.
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✓ What's Safe
- • Nori (used in sushi rolls) - lower in iodine than other varieties and generally safer
- • Limit to 1-2 servings per week to avoid excessive iodine intake
- • Choose products from reputable brands that test for heavy metals
- • Roasted seaweed snacks in small portions as an occasional treat
- • Check labels for third party testing or quality certifications
✗ What to Avoid
- • Brown seaweed varieties (kelp, kombu, wakame) - extremely high in iodine
- • Daily seaweed consumption or large portions in one sitting
- • Seaweed supplements or concentrated extracts during pregnancy
- • Products without clear sourcing or heavy metal testing
- • Hijiki seaweed - known to contain higher levels of inorganic arsenic
Most Common Ingredients in Seaweed Products
We analyzed 237 seaweed products. Here are the most common ingredients, ranked by how often they appear:
Ingredients to Watch Out For in Seaweed
These are the most common flagged ingredients across 237 seaweed products we analyzed.
seaweed
CAUTION
Seaweed is an edible marine algae consumed as food or supplement, rich in iodine and minerals. May cause neonatal thyroid dysfunction from excessive iodine exposure and some products contain concerning levels of inorganic arsenic.
Found in 60 of 237 products (25%)
kelp
CAUTION
Kelp is an edible marine algae consumed as food or supplement, rich in iodine and minerals. May cause neonatal thyroid dysfunction from excessive iodine exposure and some products contain concerning levels of inorganic arsenic.
Found in 17 of 237 products (7%)
organic seaweed
CAUTION
Organic seaweed is an edible marine algae consumed as food or supplement, rich in iodine and minerals. May cause neonatal thyroid dysfunction from excessive iodine exposure and some products contain concerning levels of inorganic arsenic.
Found in 12 of 237 products (5%)
dulse seaweed glycerite liquid extract
CAUTION
Dulse seaweed glycerite liquid extract is an edible marine algae consumed as food or supplement, rich in iodine and minerals. May cause neonatal thyroid dysfunction from excessive iodine exposure and some products contain concerning levels of inorganic arsenic.
Found in 8 of 237 products (3%)
laver
CAUTION
Laver is an edible marine algae consumed as food or supplement, rich in iodine and minerals. May cause neonatal thyroid dysfunction from excessive iodine exposure and some products contain concerning levels of inorganic arsenic.
Found in 8 of 237 products (3%)
alcohol
CAUTION
Alcohol is an intoxicating substance in beverages. Causes fetal alcohol spectrum disorder with lifelong physical and cognitive problems. No safe level exists.
Found in 7 of 237 products (3%)
licorice extract
CAUTION
Licorice extract is an herb used in teas and traditional remedies. Is associated with lower IQ and attention problems in children when consumed heavily during pregnancy.
Found in 7 of 237 products (3%)
kombu
CAUTION
Kombu is an edible marine algae consumed as food or supplement, rich in iodine and minerals. May cause neonatal thyroid dysfunction from excessive iodine exposure and some products contain concerning levels of inorganic arsenic.
Found in 6 of 237 products (3%)
Types of Seaweed
Seaweed Products We've Analyzed
We graded 237 seaweed products for pregnancy safety. 15 received an A grade.
Pregnancy Safe Seaweed Products
We found 15 pregnancy safe options. Here are some top picks.
| Grade | Product | Brand |
|---|---|---|
| A | Nagai'S, Roasted Seaweed Sushinori | Nagai |
| A | Hiziki Sea Vegetable Hand Harvested Wild | — |
| A | Irish Seamoss | Country Farms |
| A | Irish Sea Moss | Her Own |
| A | Irish Moss | Terravita |
Your Questions Answered
Can pregnant women eat seaweed?
Yes, pregnant women can eat seaweed in moderation. Seaweed provides valuable nutrients including folate, iron, and omega-3 fatty acids that support fetal development. However, because seaweed is naturally high in iodine, it's important to limit consumption to 1-2 servings per week. Nori (the seaweed used in sushi rolls) is generally the safest choice as it contains less iodine than brown varieties like kelp or kombu.
What are the risks of seaweed during pregnancy?
The main risk of eating too much seaweed during pregnancy is excessive iodine intake, which can cause thyroid dysfunction in newborns. Case reports have documented neonatal hypothyroidism linked to maternal seaweed consumption. Additionally, some seaweed products contain elevated levels of inorganic arsenic, a known toxicant. Brown seaweed varieties like kelp and kombu pose the highest risk due to their extremely high iodine content.
Why can't you eat seaweed while pregnant?
You can eat seaweed while pregnant, but it must be in moderation. The concern is that brown seaweed contains naturally high levels of iodine that can cause illness if consumed in large quantities. Food safety authorities advise pregnant and breastfeeding women to eat no more than one serving per week of brown seaweed varieties. Excessive iodine can disrupt your baby's thyroid development, potentially causing hypothyroidism that affects neurodevelopment.
Can I eat seaweed salad while pregnant?
Seaweed salad can be eaten occasionally during pregnancy, but with caution. Most seaweed salads are made with wakame, a brown seaweed that's very high in iodine. Limit seaweed salad to once per week and keep portions small. Also be mindful of the dressing and other ingredients - ensure the salad is fresh and from a reputable source. If you're craving seaweed, nori based snacks are a safer everyday alternative.
Can I eat dried seaweed while pregnant?
Dried seaweed can be eaten during pregnancy in small amounts. Dried seaweed snacks made from nori are generally the safest option as they contain less iodine per serving. However, dried kelp or kombu should be limited to occasional use due to their concentrated iodine levels. Stick to 1-2 small servings of dried seaweed per week and choose products from brands that test for heavy metals and contaminants.
What are the benefits of eating seaweed during pregnancy?
Seaweed offers several nutritional benefits during pregnancy when eaten in moderation. It's rich in folate (important for preventing neural tube defects), iron (helps prevent anemia), and iodine (essential for fetal brain development in appropriate amounts). Seaweed also provides omega-3 fatty acids, antioxidants, and fiber. The key is balancing these benefits with the risks of overconsumption by limiting intake to 1-2 servings weekly.
How Do We Score Products for Pregnancy Safety?
We analyze each product's ingredients and category to flag known risks and provide cautionary notices for general category safety concerns.
A - Safe
Excellent choice! All ingredients are considered safe during pregnancy.
What to do: Use with confidence.
B - Likely Safe
Pretty much safe with very minimal risk. Some ingredients may have limited pregnancy studies, but no significant safety concerns have been identified.
What to do: Use with confidence.
C - Limit
Contains ingredients with some pregnancy considerations. Research shows these ingredients may have limited safety data, potential for minor hormonal effects, or require caution based on animal studies.
What to do: Use sparingly and consider safer alternatives when available.
D - Caution
Similar to C grade but contains multiple cautionary ingredients. The combination increases overall concern.
What to do: Try to avoid if that makes you feel better. If you've already used it, no need to panic.
F - Avoid
Contains ingredients with established risks during pregnancy. Research shows these can cause birth defects, developmental harm, or serious maternal complications.
What to do: Do not use during pregnancy. If you've already used it, don't worry - contact your OBGYN if concerned.
References
- https://pubmed.ncbi.nlm.nih.gov/37210373/
- https://pubmed.ncbi.nlm.nih.gov/36191802/
- https://pubmed.ncbi.nlm.nih.gov/35182530/
- https://pubmed.ncbi.nlm.nih.gov/34602396/
- https://pubmed.ncbi.nlm.nih.gov/33719075/
- https://pubmed.ncbi.nlm.nih.gov/33608335/
- https://www.nhs.uk/pregnancy/keeping well/drinking alcohol while pregnant/
- https://pmc.ncbi.nlm.nih.gov/articles/PMC7061927/
- https://pmc.ncbi.nlm.nih.gov/articles/PMC7807528/
- https://en.wikipedia.org/wiki/Fetal_alcohol_spectrum_disorder
- https://pmc.ncbi.nlm.nih.gov/articles/PMC3297711/
- https://americanaddictioncenters.org/alcohol/risks effects dangers/pregnancy
- https://www.aacap.org/AACAP/Families_and_Youth/Facts_for_Families/FFF Guide/Drinking Alcohol in Pregnancy Fetal Alcohol Effects-093.aspx
- https://www.nature.com/articles/pr200789
- https://www.mayoclinic.org/diseases conditions/fetal alcohol syndrome/symptoms causes/syc-20352901
- https://my.clevelandclinic.org/health/diseases/15677-fetal alcohol syndrome
- https://limerickinc.com/blogs/more resources/why is licorice root bad for pregnancy
- https://pubmed.ncbi.nlm.nih.gov/28158597/
- https://restorativemedicine.org/library/monographs/licorice-2/
- https://www.rileychildrens.org/connections/new study suggests women should avoid eating licorice during pregnancy
