DHA shows up on almost every prenatal label, and for good reason. But "need" is a strong word, and the evidence is more nuanced than most marketing lets on. Here's what the research actually supports.
Written by Vita Globe Editorial Team | Reviewed against NIH guidance, a Cochrane systematic review and FDA/EPA advice
Do you really need DHA during pregnancy?
DHA is a building block of your baby's brain and eyes, and it builds up fastest in the third trimester[1]. A 2018 Cochrane review of 70 trials found omega-3s lowered the risk of preterm birth by about 11% and early preterm birth by about 42%[2]. Expert groups suggest aiming for at least 200 mg of DHA a day while pregnant[4], from low-mercury fish, a supplement, or both[5].
Caveat: A large 2019 trial of more than 5,000 women found no reduction in early preterm birth with fish oil[3]. Your OB or midwife can help you decide if a supplement makes sense for you.
Sources: NIH ODS (omega-3) · Cochrane 2018 · Koletzko 2008 · NEJM 2019 (ORIP) · Verified 2026-09-27
In this article
What does DHA actually do in pregnancy?
DHA (docosahexaenoic acid) is a long-chain omega-3 fat. It's one of the main structural fats in the brain and the retina, the light-sensing layer at the back of the eye. According to the NIH Office of Dietary Supplements, DHA accumulates most rapidly in the baby's brain and retina during the third trimester[1].
Your baby gets DHA from you, across the placenta during pregnancy, and later from breast milk or formula. That's the basic reason it gets so much attention on prenatal labels.
Your body can technically make DHA from ALA, the plant omega-3 in flax, chia and walnuts. The catch is that the conversion is very limited, with reported rates under 15%[1]. So eating walnuts doesn't reliably top up DHA the way eating salmon does.
Does DHA lower the risk of preterm birth?
This is where the strongest evidence sits. In 2018, a Cochrane systematic review pooled 70 randomized trials with close to 20,000 women. It found that omega-3 supplements during pregnancy reduced the risk of preterm birth (before 37 weeks) by about 11% and early preterm birth (before 34 weeks) by about 42%. The review rated that evidence high quality[2]. It also found a small reduction in low birthweight babies, and a slight increase in pregnancies running past term[2].
Then a big trial complicated the picture. The ORIP trial in Australia gave more than 5,000 pregnant women 900 mg a day of omega-3s from fish oil or a placebo, starting before 20 weeks. Early preterm birth wasn't lower in the fish oil group[3]. One idea researchers have raised is that people who already have decent omega-3 levels may gain less from adding more, but that is still being studied.
The honest summary
- DHA is a genuine building block for your baby's brain and eyes[1].
- Pooled trials suggest omega-3s may lower the risk of preterm birth[2].
- A large 2019 trial didn't find the same benefit, so the picture is still being worked out[3].
- Supplements aren't a guarantee. They're one tool your provider can help you weigh.
How much DHA do you need while pregnant?
There's no official Recommended Dietary Allowance for DHA in the U.S. The NIH sets an Adequate Intake only for total ALA, at 1.4 grams a day in pregnancy[1].
For DHA specifically, an international expert consensus recommended that pregnant and breastfeeding women aim for an average of at least 200 mg of DHA per day[4]. That's the number you'll often see echoed by clinicians.
For context, a 3-ounce serving of farmed salmon has roughly 1.24 grams of DHA, and canned sardines about 0.74 grams[1]. So two servings of salmon a week averages out well above 200 mg a day.
Can you get enough DHA from food alone?
Yes, if you eat fish. The FDA and EPA advise people who are pregnant or breastfeeding to eat 8 to 12 ounces of a variety of lower-mercury seafood each week, which is two to three servings from the "Best Choices" list[5]. Salmon, sardines, anchovies, trout and canned light tuna all qualify.
The problem is that many people don't hit that target. The NIH notes that many pregnant women don't meet the seafood recommendation[1]. Food aversions, nausea, budget and simple dislike of fish all get in the way.
That's where a supplement can help fill the gap. If you want the full food list, see our guide to omega-3 foods to eat during pregnancy.
Is taking DHA during pregnancy safe?
Omega-3 supplements are generally well tolerated. The most common side effects are mild: an unpleasant taste, bad breath, heartburn, nausea and loose stools[6]. The FDA has said that supplements providing up to 5 grams a day of EPA plus DHA are safe, which is far more than any prenatal provides[1].
Two things are worth flagging to your provider. Fish oil can affect clotting times if you take a blood thinner such as warfarin[1], and fish oil isn't suitable if you have a fish allergy. Worried about mercury? We cover that in Fish Oil and Mercury: Is It Safe in Pregnancy?
One more thing: DHA doesn't replace folic acid. You still need a prenatal vitamin with folic acid, ideally starting before conception. See when to start prenatal vitamins.
Our option
Vita Globe Prenatal Fish Oil Gummies
Our Prenatal Fish Oil Gummies pair omega fatty acids from fish oil with vitamins that include folic acid (vitamin B9), in a raspberry and lemon chewable gummy. Suggested use is 2 gummies once daily; they're gluten-free, non-GMO and made without artificial colors or flavors. It's one way to add omega-3s if fish isn't on your plate most weeks. The exact DHA, EPA and folic acid amounts are on the Supplement Facts panel on the product page, so bring it to your OB or midwife. It contains fish, and it isn't a substitute for a prenatal vitamin your provider has recommended.
Frequently asked questions
When should I start taking DHA in pregnancy?
The large ORIP trial started omega-3s before 20 weeks[3], and DHA builds up fastest in the third trimester[1]. Ask your OB or midwife what timing makes sense for you. Many people start when they start their prenatal.
Is DHA the same as fish oil?
Not exactly. Fish oil is the source; DHA is one of the omega-3s inside it, alongside EPA[1]. Read more in DHA vs. EPA: What's the Difference?
Can I get DHA if I'm vegetarian?
Algal oil supplements provide DHA without fish, usually around 100 to 300 mg[1]. Plant ALA sources like flax and chia convert to DHA poorly.
Do I need DHA if I eat salmon every week?
If you regularly eat 8 to 12 ounces of lower-mercury fish a week, you may already be meeting the target[5]. Researchers are still studying whether extra omega-3s add much for people who already eat fish regularly[3]. Your provider can help you decide.
Does DHA make babies smarter?
DHA is a structural part of the brain[1], but supplements aren't proven to raise a child's IQ. We'd be skeptical of any product that promises that.
Sources
- NIH Office of Dietary Supplements. Omega-3 Fatty Acids: Fact Sheet for Health Professionals. Updated September 20, 2026. ods.od.nih.gov
- Middleton P, Gomersall JC, Gould JF, Shepherd E, Olsen SF, Makrides M. Omega-3 fatty acid addition during pregnancy. Cochrane Database Syst Rev. 2018;11:CD003402. doi:10.1002/14651858.CD003402.pub3
- Makrides M, Best K, Yelland L, et al. A randomized trial of prenatal n−3 fatty acid supplementation and preterm delivery. N Engl J Med. 2019;381(11):1035-1045. doi:10.1056/NEJMoa1816832
- Koletzko B, Lien E, Agostoni C, Böhles H, Campoy C, et al. The roles of long-chain polyunsaturated fatty acids in pregnancy, lactation and infancy: review of current knowledge and consensus recommendations. J Perinat Med. 2008;36(1):5-14. doi:10.1515/JPM.2008.001
- U.S. Food and Drug Administration and U.S. Environmental Protection Agency. Advice about Eating Fish: For Those Who Might Become or Are Pregnant or Breastfeeding and Children Ages 1–11 Years. Updated March 5, 2024. fda.gov
- National Center for Complementary and Integrative Health. Omega-3 Supplements: What You Need To Know. Updated November 2024. nccih.nih.gov
About the Vita Globe Editorial Team
The Vita Globe Editorial Team researches and writes our wellness content, working from peer-reviewed research, systematic reviews and guidance from bodies such as the NIH and the FDA. We cite our sources inline and update articles when the evidence changes.
These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease. This article is for informational purposes only and is not a substitute for medical advice. Talk to your healthcare provider before starting any new supplement, particularly if you are pregnant, nursing, taking medication, or caring for a child.
