Can I Take Fish Oil While Pregnant? | What Experts Advise

Yes, taking fish oil during pregnancy is generally considered safe and may support your baby’s brain and eye development.

You’ve probably heard the advice to eat more fish when you’re expecting, but mercury warnings make it confusing. Some people assume all fish oil capsules are interchangeable — they’re not. The type and dose matter a great deal during pregnancy.

The honest answer is that omega-3 supplements are widely recommended for pregnant women, but the devil is in the details. This article walks through safe dosing, which supplements to choose, and how to balance food and pills for the best support for you and your baby.

Omega-3 During Pregnancy: What You Need to Know

Omega-3 fatty acids, particularly DHA and EPA, are essential for fetal brain and eye development. During the third trimester, the baby’s brain accumulates DHA rapidly, so meeting your intake is especially important.

The standard recommendation is to aim for 200 to 300 mg of DHA per day during pregnancy, according to a Mayo Clinic health report. That equals about two servings of low-mercury fish per week, such as salmon, sardines, or anchovies.

One important caveat: supplements made from fish liver oils should be avoided. They can contain high levels of vitamin A, which may be harmful in large amounts. Always choose a purified fish oil made from the body of the fish, not the liver.

Why Pregnant Women Reach for Fish Oil

Many moms-to-be hear that fish oil supports baby’s development and want to be proactive. The main reason is the role DHA plays in the baby’s nervous system, but there are other potential benefits worth knowing.

• Brain development support: DHA is a structural component of the brain and retina. Adequate intake during pregnancy may help with cognitive function in early childhood, though evidence is mixed.
• Eye health: DHA accumulates in the retina, and some studies suggest it supports visual development. The effect is modest but meaningful for many babies.
• Preterm birth reduction: Higher doses of omega-3 (up to 1,000 mg per day) have shown promise in lowering the risk of early delivery, though not every study agrees.
• Food-first approach: Getting omega-3s from fish is ideal. Two servings per week provide roughly the recommended amount of DHA, plus other nutrients like vitamin D and protein.

The catch is that not all omega-3 sources are equal. Most prenatal vitamins contain some DHA, but often less than the target dose, so a separate fish oil supplement may be needed.

How Much Omega-3 Is Recommended?

The amount of omega-3 you need depends partly on whether you get it from food or supplements. Per the safe fish servings pregnancy guide from Mayo Clinic, pregnant women should eat 8 to 12 ounces of low-mercury fish per week, which provides roughly 100 to 250 mg of omega-3s daily.

For supplements, the European Food Safety Authority recommends at least 250 mg of DHA plus EPA per day for the general population, and an additional 100–200 mg of DHA during pregnancy. That brings the total to roughly 350–450 mg daily of combined DHA and EPA.

Going above 3,000 mg per day is not recommended because high doses may increase bleeding risk. Always check the label for DHA and EPA content, and talk to your obstetrician about your specific dose.

As you can see, a single serving of salmon covers the daily DHA recommendation. Many women find that eating fish twice a week is enough, but if you don’t enjoy fish, supplements are a reliable option.

What About Fish Oil Supplements?

If you’re not a fan of fish, a supplement can fill the gap. Here are factors to consider before picking a bottle off the shelf.

1. Check for purity certifications: Look for third-party testing seals (USP, NSF) to ensure the oil is free of mercury, PCBs, and other contaminants.
2. Avoid fish liver oils: Cod liver oil, for example, is high in vitamin A and should not be used during pregnancy. Stick to body-oil supplements.
3. Match the DHA dose to recommendations: Aim for at least 200 mg of DHA per day. Many prenatal vitamins contain 100–150 mg, so you may need an additional supplement.
4. Be mindful of the EPA:DHA ratio: Some supplements are high in EPA, which may have blood-thinning effects at high doses. DHA is the priority during pregnancy.

Most women find a 500 mg capsule of fish oil (containing both DHA and EPA) fits well into a daily routine. Start with a low dose and increase gradually to avoid burping or stomach upset.

Balancing Benefits and Safety

The evidence for fish oil during pregnancy is generally positive, but some nuance is important. A review hosted by NIH examined how much DHA you get from food — fish servings DHA amount notes that two servings of fish per week provide about 100 to 250 mg of omega-3s, with 50 to 100 mg as DHA. That means even if you eat fish regularly, you might fall short of the 200–300 mg DHA target.

Some studies have looked at whether fish oil supplements affect infant neurocognition. Results are mixed: a 2020 review found no significant effect on birth weight or head circumference, while other research points to modest benefits for attention and visual acuity in early childhood. The evidence isn’t strong enough to say it’s a guaranteed boost, but it is enough to support the recommendation.

The safety profile is well established at typical doses. The main concern is high-dose supplements (over 3,000 mg per day) which may increase bleeding risk. For most women, a daily dose of 200–500 mg of combined DHA and EPA is well within safe limits.

A simple rule: stick with smaller, oily fish like salmon, sardines, and anchovies. They deliver more DHA with less mercury risk than larger predatory fish.

The Bottom Line

Taking fish oil during pregnancy is generally safe and may support your baby’s development. Aim for 200 to 300 mg of DHA daily from a combination of low-mercury fish or a purified supplement. Skip fish liver oils and keep your total omega-3 intake under 3,000 mg per day.

Your obstetrician or midwife can help you pick the right supplement and dose based on your diet and any other medications you’re taking, including blood thinners. A quick chat can turn the general guidelines into a plan that fits your specific needs.