Many prenatal vitamins list DHA on the front of the bottle, and many leave it out entirely. If you're comparing prenatals, it's worth knowing what DHA is, how much experts suggest during pregnancy and breastfeeding, and whether your diet already provides enough.

What DHA is

DHA, short for docosahexaenoic acid, is an omega-3 fatty acid. It is a major structural fat in the brain and in the retina, the light-sensing layer at the back of the eye.

The body can make a small amount of DHA from ALA, the plant-derived omega-3 found in flaxseed, chia and walnuts, but the conversion is limited. For practical purposes, most DHA has to come from food or supplements.

Why DHA matters in pregnancy and breastfeeding

A baby's brain grows rapidly during the third trimester and the first years of life, and DHA accumulates in the brain and eyes during that time. During pregnancy, DHA passes to the baby through the placenta. After birth, breastfed babies receive DHA through breast milk, and the amount in breast milk reflects how much DHA the mother eats.

How much DHA to aim for

An international expert group, the Perinatal Lipid Intake Working Group, reviewed the research for the European Commission. Its consensus, published in the British Journal of Nutrition in 2007, recommends that pregnant and breastfeeding women aim for an average of at least 200 mg of DHA a day. The same group noted that clinical trials have used up to 1 gram of DHA a day without significant adverse effects.

The United States has no official daily recommendation for DHA. Instead, the FDA and the Environmental Protection Agency advise pregnant and breastfeeding women to eat 8 to 12 ounces of a variety of low-mercury seafood each week, which is about two to three servings.

Getting DHA from food

Fatty fish are the richest food source. Salmon, sardines, anchovies, herring, trout and Atlantic mackerel are high in DHA and are on the FDA's list of "best choices" for low mercury. Shrimp, tilapia and cod are also low in mercury but contain much less DHA.

The FDA advises pregnant and breastfeeding women to avoid fish highest in mercury, including king mackerel, marlin, orange roughy, shark, swordfish, tilefish from the Gulf of Mexico and bigeye tuna.

Eggs from hens fed omega-3-enriched feed provide some DHA, though far less than fish.

Many women don't reach two servings of fish a week, whether because of taste, aversions during pregnancy, cost, kashrut considerations or a vegetarian diet. For them, a prenatal or separate supplement with DHA fills the gap.

Fish oil or algal oil?

DHA supplements come from two main sources. Fish oil is extracted from fatty fish. Algal oil comes from microalgae, which are the original source of the DHA in fish: fish accumulate it by eating algae, or by eating smaller fish that did.

Algal oil is a fish-free source of DHA, which suits people who avoid fish or prefer a plant-based source of the oil itself. Both forms are used in prenatal supplements.

How to read the label

• Look for the amount of DHA in milligrams, listed separately from "omega-3" or "fish oil." A softgel with 1,000 mg of fish oil may contain far less than 1,000 mg of DHA.
• Check the serving size. Some prenatals provide their DHA across two or more softgels.
• Check the source, fish oil or algal oil, if that matters to you.

DHA in Zahler prenatals

Prenatal +DHA 300 provides 300 mg of DHA from algal oil in each two-softgel serving, alongside a full prenatal multivitamin. That amount on its own exceeds the 200 mg consensus target. It's Zahler's most-reviewed prenatal, with more than 140 reviews and an average of 4.8 stars.

Mighty Mini Prenatal + DHA provides 100 mg of DHA from algal oil in one small softgel, along with 19 vitamins and minerals. It's a good fit for women who prefer a single small pill and also eat fish once or twice a week.

300 mg DHA per serving

Prenatal +DHA 300

★★★★★ 4.8 from 140+ reviews

A full prenatal plus 300 mg of DHA from algal oil in two softgels a day.

Shop Prenatal +DHA

100 mg DHA per softgel

Mighty Mini Prenatal + DHA

★★★★★ 4.7 from 100+ reviews

19 vitamins and minerals plus 100 mg of DHA in one small softgel a day.

Shop Mighty Mini

This article is for informational purposes only and is not a substitute for professional medical advice. Always consult your healthcare provider about your individual needs. These statements have not been evaluated by the Food and Drug Administration. These products are not intended to diagnose, treat, cure or prevent any disease.

Sources

• Koletzko B, Cetin I, Brenna JT. "Dietary fat intakes for pregnant and lactating women." British Journal of Nutrition, 2007.
• Koletzko B, et al. "The roles of long-chain polyunsaturated fatty acids in pregnancy, lactation and infancy." Journal of Perinatal Medicine, 2008.
• U.S. Food and Drug Administration and Environmental Protection Agency. "Advice about Eating Fish."
• National Institutes of Health, Office of Dietary Supplements. "Omega-3 Fatty Acids" fact sheet.
• Zahler Supplement Facts panels: Mighty Mini Prenatal + DHA and Prenatal +DHA 300.