Omega-3 During Pregnancy: Benefits, Safety & Best Sources
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Omega-3 fatty acids are important during pregnancy because DHA and EPA contribute to normal cell membranes, while DHA has a particularly important structural role in the developing brain and retina.
The safest and most practical way to improve omega-3 intake is usually to eat a variety of lower-mercury fish and seafood while following pregnancy-specific food-safety guidance. Supplements may be useful when fish intake is low, but the product, dose, source, purity, and vitamin content all matter.
This guide explains omega-3 during pregnancy, DHA and EPA, possible benefits, safe fish choices, mercury precautions, fish-oil and algal-oil supplements, cod liver oil concerns, dosage, timing, side effects, medication interactions, and breastfeeding.
Why Omega-3 Matters During Pregnancy
Omega-3 fatty acids are part of cell membranes and participate in normal signalling throughout the body.
During pregnancy, long-chain omega-3s are relevant to:
- Fetal brain development
- Retinal and visual development
- Nervous-system development
- Normal cell-membrane structure
- Maternal dietary quality
DHA vs EPA During Pregnancy
| Omega-3 | Main Role | Pregnancy Relevance |
|---|---|---|
| DHA | Major structural fatty acid in the brain and retina | Usually the main focus of prenatal omega-3 products |
| EPA | Supports signalling pathways and helps provide long-chain omega-3 balance | Often included with DHA in fish-oil products |
| ALA | Essential plant omega-3 used for energy and limited conversion | Important in the diet but converts inefficiently to DHA |
DHA and Baby Brain Development
DHA is highly concentrated in the brain and is incorporated into neural tissue during fetal development.
This does not mean that taking increasingly large amounts produces a smarter baby. Development depends on the entire nutritional pattern, prenatal care, genetics, maternal health, sleep, substance avoidance, and many other factors.
DHA and Eye Development
DHA is also concentrated in the retina and contributes to normal visual development.
A balanced prenatal diet that includes appropriate seafood can supply DHA together with protein, iodine, selenium, vitamin D, and other nutrients.
Possible Pregnancy Benefits
Research has examined omega-3 intake in relation to:
- Fetal growth
- Gestational length
- Preterm birth
- Birth weight
- Infant visual and cognitive development
- Maternal mood
Results vary according to baseline fish intake, dose, formulation, timing, and study population. Omega-3 should be considered part of prenatal nutrition rather than a guarantee against complications.
How Much Fish Should You Eat During Pregnancy?
FDA recommends 8 to 12 ounces per week from lower-mercury choices for people who are pregnant or breastfeeding.
That equals approximately two to three servings per week.
| Weekly Target | Approximate Frequency | Best Approach |
|---|---|---|
| 8 to 12 ounces | Two to three servings | Choose a variety of lower-mercury fish |
| One serving | About 4 ounces before cooking | Use current FDA/EPA serving guidance |
| Local or self-caught fish | Depends on advisory | Check local contamination guidance |
Best Fish During Pregnancy
Lower-mercury options commonly included among FDA “Best Choices” include:
- Salmon
- Sardines
- Trout
- Herring
- Anchovies
- Shrimp
- Pollock
- Tilapia
- Light canned tuna
- Oysters
- Clams
Fatty fish such as salmon, sardines, trout, and herring are particularly useful because they provide DHA and EPA.
Fish to Avoid During Pregnancy
FDA advises avoiding fish in the highest-mercury category, including:
- Shark
- Swordfish
- King mackerel
- Marlin
- Orange roughy
- Bigeye tuna
- Tilefish from the Gulf of Mexico
Light Tuna vs Albacore Tuna
Light canned tuna is generally lower in mercury than albacore or white tuna.
ACOG guidance advises limiting albacore tuna to 6 ounces per week during pregnancy.
Fresh, Frozen, and Canned Fish
Fresh, frozen, and canned fish can all contribute to omega-3 intake.
Canned salmon and sardines are convenient, affordable, and shelf-stable. Check sodium if you need to limit salt.
Food Safety During Pregnancy
Pregnancy increases vulnerability to certain foodborne infections.
Safer seafood practices include:
- Cook fish and shellfish thoroughly
- Avoid raw or undercooked seafood
- Avoid refrigerated smoked seafood unless cooked in a dish
- Prevent cross-contamination
- Refrigerate leftovers promptly
- Buy seafood from reputable sources
Can You Take Fish Oil During Pregnancy?
Fish-oil supplements may be appropriate when dietary EPA and DHA intake is low.
Before choosing a product, review:
- DHA per serving
- EPA per serving
- Number of capsules
- Fish source
- Purity and contaminant testing
- Added vitamin A and vitamin D
- Medication and allergy history
Algal Oil During Pregnancy
Algal oil is a vegetarian or vegan source of DHA and, in some products, EPA.
Potential advantages include:
- No fish-derived ingredients
- Direct DHA
- Less fishy aftertaste for some users
- Suitability for people who avoid seafood
Check whether the product contains DHA only or both DHA and EPA.
Cod Liver Oil Warning
Cod liver oil is different from ordinary fish oil because it can contain substantial vitamin A and vitamin D.
Excess preformed vitamin A during pregnancy can cause birth defects.
How Much DHA During Pregnancy?
There is no single universally adopted prenatal DHA supplement dose that applies to everyone.
Many professional and expert recommendations use at least 200 mg DHA daily as a practical benchmark, especially when seafood intake is low. However, the appropriate amount depends on diet, prenatal vitamins, health history, and professional guidance.
Do not assume that a higher-dose product is better.
ALA Intake During Pregnancy
The U.S. adequate intake for ALA during pregnancy is 1.4 g per day.
Sources include:
- Ground flaxseed
- Chia seeds
- Walnuts
- Hemp seeds
- Canola oil
- Soybean oil
- Soy foods
ALA is useful and essential, but conversion to DHA is limited.
When Should You Start Omega-3?
A healthy dietary pattern is valuable before conception and throughout pregnancy.
DHA accumulation in fetal neural tissue becomes especially important later in pregnancy, but there is no need to wait until the third trimester to improve diet quality.
Discuss supplements early if you:
- Rarely eat seafood
- Follow a vegan diet
- Have a fish allergy
- Use blood-thinning medication
- Take multiple prenatal products
- Have a high-risk pregnancy
Best Time to Take Prenatal Omega-3
There is no universally superior time of day.
Take omega-3 with a meal to reduce:
- Fishy burps
- Nausea
- Heartburn
- Abdominal discomfort
People with pregnancy-related nausea may tolerate it better with lunch or dinner rather than first thing in the morning.
Can Omega-3 Be Taken With a Prenatal Vitamin?
Usually yes, but check for overlapping ingredients.
Review:
- DHA
- EPA
- Vitamin A
- Vitamin D
- Iron
- Iodine
- Choline
Some prenatal vitamins already contain DHA, while others do not.
Possible Side Effects During Pregnancy
Common omega-3 side effects include:
- Fishy aftertaste
- Burping
- Heartburn
- Nausea
- Loose stools
- Abdominal discomfort
Taking the supplement with food and using a concentrated product requiring fewer capsules may help.
Bleeding and Medication Interactions
Omega-3 can influence platelet activity.
Discuss higher-dose products if you use:
- Aspirin prescribed during pregnancy
- Heparin
- Enoxaparin
- Warfarin in special clinical circumstances
- Other anticoagulant or antiplatelet medicines
Fish and Shellfish Allergy
People with fish allergy should not assume purified fish oil is automatically safe.
Algal oil may be a better option, but all ingredients and manufacturing warnings should be checked.
Omega-3 While Breastfeeding
DHA remains relevant during breastfeeding because maternal intake can influence breast-milk DHA.
FDA continues to recommend 8 to 12 ounces of lower-mercury seafood per week during breastfeeding.
The U.S. adequate intake for ALA during breastfeeding is 1.3 g daily.
How to Choose a Prenatal Omega-3 Supplement
| Label Item | What to Check | Why It Matters |
|---|---|---|
| DHA | Milligrams per serving | Main prenatal omega-3 focus |
| EPA | Milligrams per serving | May be included alongside DHA |
| Serving size | Number of capsules | The listed amount may require several capsules |
| Source | Fish or algae | Affects dietary preference and allergy |
| Vitamin A | Amount and form | Excess preformed vitamin A is unsafe in pregnancy |
| Quality testing | Contaminants, oxidation, purity | Supports product quality |
Common Pregnancy Mistakes
Avoiding All Fish Because of Mercury
Current guidance recommends lower-mercury seafood, not complete seafood avoidance.
Choosing Cod Liver Oil Without Checking Vitamin A
Preformed vitamin A can be excessive.
Using Total Fish-Oil Weight as the DHA Dose
Check DHA and EPA separately.
Taking Multiple Prenatal Products
Ingredients may overlap.
Assuming More DHA Is Always Better
High doses are not automatically more beneficial.
Ignoring Food Safety
Raw or undercooked seafood can carry infection risk during pregnancy.
Who Should Ask a Healthcare Professional First?
- People taking aspirin or anticoagulants
- People with a bleeding disorder
- People with fish or shellfish allergy
- People carrying twins or higher-order multiples
- People with significant liver, pancreatic, or gastrointestinal disease
- People with severe pregnancy nausea or vomiting
- People using cod liver oil or multiple supplements
- People with a high-risk pregnancy
Related Omega-3 Guides
- The Complete Guide to Omega-3 Supplements
- Omega-3 Benefits
- EPA vs DHA
- Fish Oil vs Omega-3
- Foods High in Omega-3
- Omega-3 Dosage
- Omega-3 Side Effects
- Best Time to Take Fish Oil
Final Thoughts
Omega-3 fatty acids are an important part of pregnancy nutrition, with DHA playing a major structural role in the developing brain and retina.
FDA recommends 8 to 12 ounces of lower-mercury seafood each week during pregnancy and breastfeeding. Salmon, sardines, trout, herring, shrimp, and light canned tuna are practical choices.
When seafood intake is low, fish oil or algal oil may be considered. Check DHA, EPA, serving size, purity testing, and vitamin A content. Avoid high-mercury fish and do not use cod liver oil as a prenatal omega-3 without professional guidance.
Frequently Asked Questions
Is omega-3 safe during pregnancy?
Omega-3 from lower-mercury seafood is recommended as part of a healthy pregnancy diet. Supplements may also be appropriate when selected carefully.
Why is DHA important during pregnancy?
DHA is a major structural fatty acid in the developing brain and retina.
How much fish should pregnant people eat?
FDA recommends 8 to 12 ounces, or about two to three servings, of lower-mercury fish per week.
What fish are best during pregnancy?
Salmon, sardines, trout, herring, shrimp, pollock, and light canned tuna are commonly lower-mercury options.
What fish should be avoided?
Avoid high-mercury fish such as shark, swordfish, king mackerel, marlin, orange roughy, bigeye tuna, and Gulf of Mexico tilefish.
Can pregnant people take fish oil?
Yes, when appropriate, but check DHA, EPA, purity, allergy warnings, vitamin A, and medication interactions.
Is algal oil safe during pregnancy?
Algal oil is a direct vegetarian or vegan source of DHA and may be suitable when seafood intake is low.
Is cod liver oil safe during pregnancy?
It may contain excessive preformed vitamin A. Do not use it without professional review of the exact product.
How much DHA is needed during pregnancy?
Many recommendations use at least 200 mg DHA daily as a practical benchmark, but the appropriate amount depends on diet and professional guidance.
When should omega-3 be started?
A healthy omega-3-rich diet is useful before conception and throughout pregnancy. Supplements can be discussed early when seafood intake is low.
Can omega-3 be taken with a prenatal vitamin?
Usually yes, but check for duplicate DHA, EPA, vitamin A, and vitamin D.
Can omega-3 cause side effects in pregnancy?
Possible effects include fishy burps, heartburn, nausea, loose stools, and abdominal discomfort.
Can omega-3 interact with low-dose aspirin?
Higher-dose omega-3 may matter for bleeding risk. Do not stop aspirin; ask the prescriber to review the supplement.
Should omega-3 continue while breastfeeding?
DHA remains relevant during breastfeeding, and FDA continues to recommend lower-mercury seafood intake.
About the Author
Olivia Bennett is a maternal nutrition writer specializing in prenatal nutrition, omega-3 fatty acids, pregnancy food safety, supplement comparisons, and evidence-informed wellness education.
Content reviewed and published by GetMySupplement Editorial Team. Last updated August 2, 2026.
This article is for educational purposes only and should not be considered medical advice. Pregnancy nutrition and supplement needs vary. Consult a qualified prenatal healthcare professional before starting a fish-oil, algal-oil, or cod-liver-oil product, especially if you take aspirin or anticoagulants, have a bleeding disorder, allergy, high-risk pregnancy, or use multiple supplements.
References
- NIH Office of Dietary Supplements: Omega-3 Fatty Acids Fact Sheet for Health Professionals
- NIH Office of Dietary Supplements: Dietary Supplements and Life Stages—Pregnancy
- U.S. FDA: Advice About Eating Fish
- American College of Obstetricians and Gynecologists: Healthy Eating During Pregnancy
- American College of Obstetricians and Gynecologists: Breastfeeding Your Baby
- MedlinePlus: Pregnancy and Nutrition