Beyond the Prenatal: Do You Need Omega-3 Supplements During Pregnancy?

Eating a balanced diet and taking prenatal vitamins are important habits during pregnancy. Some vitamins and nutrients, like folic acid, are part of nearly every prenatal vitamin. But others, like omega-3 fatty acids (omega-3s), may not always be included — even though they’re an important supplement you should take during pregnancy. 

But before you pick up a bottle of omega-3s from the supplements aisle, you may still have a few questions. Like, what are omega-3s and how much do you need to take? Let’s discuss.

What are omega-3 fatty acids?

Omega-3s are polyunsaturated fatty acids. They support many of the body’s systems and organs, including the:

• Lungs

• Heart 

• Immune system

• Brain

• Eyes

The human body can’t make omega-3s on its own, so you have to get them from foods or supplements. The three main types are:

• Alpha-linolenic acid (ALA)

• Eicosapentaenoic acid (EPA)

• Docosahexaenoic acid (DHA)

EPA and DHA are considered “active” forms of omega-3s. This means they’re ready to be used by the body. ALA is not an active omega-3. The body must break down ALA into EPA and DHA in order to use it.

Why are omega-3s important during pregnancy?

During pregnancy, there’s a higher need for omega-3s to support both the pregnant woman and growing baby. 

Benefits to the pregnant woman

According to studies, there are two main benefits of omega-3s for a pregnant woman:

1. Reduced risk of preeclampsia. Preeclampsia can happen when pregnancy causes high blood pressure. It can damage your body and put your baby at risk without proper treatment.

2. Reduced risk of postpartum depression. This is a mental health condition that causes feelings of ongoing sadness after giving birth. Studies have shown that omega-3s can reduce the risk of postpartum depression. They may also help reduce symptoms of depression during pregnancy, but the evidence for this isn’t as strong.

Benefits to the growing baby

Omega-3s are also important for the growing baby. They’re needed to develop a healthy brain and eyes. DHA is particularly important for this. An unborn baby’s brain and eyes begin storing DHA in the womb, especially in the second half of pregnancy.

Getting enough omega-3s during pregnancy may also lower the risk of preterm birth and low birth weight. Taking omega-3s during pregnancy may also result in higher intelligence and memory scores in children later in life. But the research on this is mixed.

Prevention of autism spectrum disorder

Newer research suggests people with autism spectrum disorder (ASD) may have low levels of omega-3s. Some studies have shown that omega-3 supplements improve ASD symptoms in children. But the research on this isn’t clear.

One study (the MARBLES study) looked at whether increased omega-3s during pregnancy could help prevent autism. Researchers found that women who reported consuming more omega-3s during the second half of pregnancy had a 40% lower risk of having a child with ASD. But when the women’s omega-3 levels were measured during the third trimester, higher levels didn't correlate to a lower risk of ASD. 

This tells us we need more research before we can determine if omega-3 supplementation during pregnancy can help prevent ASD. 

What dose of omega-3s is best during pregnancy?

The National Institutes of Health (NIH) recommends 1.4 grams of ALA per day for pregnant women. Remember that ALA has to be converted to EPA and DHA by the body for it to work. How much ALA becomes DHA in the body depends on many factors, including genetics. 

Since DHA is important for a growing baby’s development, it’s important to pay attention to how much you’re getting. It’s recommended to get at least 200 mg of DHA daily while pregnant. And some studies have shown that higher doses may be even better. 

But how much omega-3s are too much? The upper limit isn’t completely clear. In pregnant women, doses of up to 1000 mg of DHA or 2,700 mg of DHA/EPA have been used without significant side effects. 

The side effects of omega-3s can include unpleasant taste, smelly breath and sweat, as well as an upset stomach. 

Where can I find omega-3s?

Omega-3s are found in both plant and animal-based foods as well as OTC supplements. Many prescription prenatal vitamins also contain them. Keep in mind that foods and supplements have varying amounts of DHA in them. Just because a food or supplement is high in total omega-3s doesn’t mean it’s high in DHA.

Food sources

Certain plant oils — like flaxseed and canola — are high in ALA. There are also foods — like some eggs — that have been fortified with extra omega-3s. 

Some examples of the typical amount of omega-3s in food sources include:

• Canola oil (1 tablespoon): 1,300 mg of ALA

• Chia seeds (1 oz): 5,000 mg of ALA

• Atlantic Salmon (3 oz): 1200 mg of DHA and 590 mg of EPA

• Light tuna (3 oz): 170 mg of DHA and 20 mg of EPA

The American College of Obstetricians and Gynecologists recommends getting at least two servings of fish or seafood per week when you’re pregnant. That’s a total of 8 to 12 ounces of seafood per week.

Keep in mind that some fish may be high in mercury. Too much mercury can negatively affect a baby’s developing brain. So it’s a good idea to consume seafood that’s low in mercury and high in DHA. Some examples include:

• Shrimp

• Salmon

• Scallops

• Light tuna

Supplements 

Omega-3s supplements come from both plant and animal sources. Some of these include:

• Animal based: Fish oil, krill oil, cod liver oil

• Plant based: Algae oil, flaxseed oil

One type of supplement is not necessarily better than another. But different supplements have varying omega-3s. For example, fish oil contains DHA and EPA while algae oil is mostly DHA. 

How to choose an OTC supplement

When choosing an OTC supplement, it’s important to read the back of the label to determine how much omega-3s are in it. You’ll want to make sure you’re getting enough omega-3s everyday based on your healthcare provider’s recommendation. 

A typical fish oil supplement comes as 1000 mg of fish oil, which provides 180 mg of EPA and 120 mg of DHA. So taking 1 to 2 doses of a supplement daily, along with an omega-3 rich diet, may provide what you need. But amounts can vary between brands, and don’t forget there may be additional omega-3s in your prenatal vitamin. If you’re not sure how much DHA you’re getting, or having trouble choosing a supplement, remember that your pharmacist and healthcare provider are here to help.

Look for supplements that are verified by the U.S. Pharmacopeia (USP). This helps you ensure the supplement contains what it says it does. Look for a “USP-verified” mark on the bottle. You can also search for USP-verified products directly from their website. Another organization that tests supplements is NSF International. Products that pass NSF International testing also have a unique mark on the bottle. You can search for NSF-verified supplements here.

What’s the best source of omega-3s during pregnancy?

It’s important to get enough omega-3s during pregnancy. But where they come from isn’t as important. 

It may be hard to get the amount of omega-3s you need every day from your diet alone. So it may be best to combine a daily omega-3 supplement with 2 servings of low-mercury seafood per week.

Your healthcare provider can help you decide how best to meet your omega-3 needs during pregnancy. 

When should you start taking omega-3 supplements? 

If you don’t think you’re getting enough omega-3s from your diet, it’s a good idea to start taking omega-3s as soon as you become pregnant. You can also add them to your routine as soon as you begin trying to conceive.

Can I take omega-3s with other medications?

Omega-3 fatty acids don’t have significant interactions with other medications. But at high doses, they may increase your risk of bleeding. So it’s important to talk to your healthcare provider before adding them to your daily routine.

You should also make sure that you keep an updated medication list that includes any prescription medications or OTC supplements you take. This will help make sure your healthcare provider and pharmacist are aware of any potential omega-3 interactions. 

Why trust our experts?

Written by:

Nicole E. Cieri-Hutcherson, PharmD, BCPS, NCMP

Nicole E. Cieri-Hutcherson, PharmD, BCPS, NCMP, has over a decade of experience as a pharmacist, professor, and researcher. She was a full-time clinical professor in the pharmacy practice department at D’Youville School of Pharmacy before subsequently joining the faculty of the pharmacy practice department at the University at Buffalo School of Pharmacy and Pharmaceutical Sciences.

Edited by:

Stacia Woodcock, PharmD

Stacia Woodcock, PharmD, is a pharmacy editor for GoodRx. She earned her Doctor of Pharmacy degree from the University of Kentucky and is licensed in New York and Massachusetts.

Reviewed by:

Amy B. Gragnolati, PharmD, BCPS

Amy Gragnolati, PharmD, BCPS, is a pharmacy editor for GoodRx. Amy currently holds her pharmacist license in Georgia and California.

Our editorial standards

Meet our experts