Omega-3 fatty acids

You’ve probably heard that eating healthy means cutting down on fats. Yes, it’s best to limit the donuts and cheeseburgers and French fries. But not all fats are bad for you. Some can help your brain and heart work. And some are can help your baby develop in the womb.

Omega-3 fatty acids are a good kind of fat. They’re good for both you and your baby during pregnancy. There are three main kinds: (Their names are really long, so it’s OK to just use the letters.)

  1. Alpha-linolenic acid (ALA). This kind can’t be produced by your body. You have to get it through foods, like walnuts and soybeans.
  2. Docosahexaenoic acid (DHA). This kind helps your baby’s brain and eyes develop in the womb. Your body makes it on its own, but the best way to get it is through food or a supplement. A supplement is a product you take to make up for certain nutrients that you don’t get enough of in the foods you eat. For example, you can take a DHA supplement.
  3. Eicosapentaenoic acid (EPA). Like DHA, your body also makes this kind, but it’s best to get it through food or a supplement.

Why do you need omega-3 fatty acids? 

Omega-3 fatty acids can improve your overall health. They:

  • Help lower blood pressure and maintain heart health
  • Help reduce conditions, like high cholesterol and clogged arteries, that can lead to heart disease.
  • May reduce the risk of heart attacks and strokes
  • Help brain health throughout life

If you’re pregnant or breastfeeding, omega-3 fatty acids—especially DHA—are important for your baby’s health. DHA is the most common omega-3 in the brain and eyes. It helps support your baby's brain and eye development.

What’s the best way to get omega-3 fatty acids? 

If you’re pregnant or breastfeeding, you need 200 milligrams of DHA each day. Here’s how you can get the right amount of DHA and other omega-3 fatty acids:

From food

  • Fish, including salmon, herring, sardines and fresh-water trout. You can eat up to 12 ounces per week of these fish. You can eat up to 6 ounces per week of albacore (white) tuna. It’s OK to eat these fish because they don’t contain a lot of mercury, a metal that can be harmful to a baby during pregnancy. Fish have DHA because of what they eat in the wild. Farm-raised fish may not contain DHA unless they’re fed food that has a lot of DHA.
  • Nuts
  • Vegetable oils, like canola, soybean and olive oil
  • Foods that have DHA added to them, like orange juice, milk and eggs. Look for the word “fortified” on the package.

Algae oil and fish oil, like cod liver oil, are good sources of omega-e fatty acids. But taking fish oil products and a prenatal vitamin can cause you to get too much of certain vitamins, like A, D and E. Too much of these vitamins can be harmful. Too much fish oil also can lead to bleeding problems, like nosebleeds and blood in the urine. Talk to your health care provider before taking any fish oil products.

You may have heard that flaxseed and flaxseed oils are good sources of omega-3 fatty acids. Some studies on animals have shown that flaxseed can be harmful during pregnancy. We don’t know enough about the effects of flaxseed on human pregnancy. So it’s best not to use flaxseed or flaxseed oil if you’re pregnant or breastfeeding.

From a supplement
If you don’t get enough DHA from food, take a supplement that contains at least 200 milligrams of DHA each day. Many prenatal vitamins (vitamins made just for pregnant women) include DHA. Talk to your health care provider before you take any vitamins or supplements to make sure they’re safe for you during pregnancy.

Last reviewed July 2012

Funding for this article was provided in part by Martek. The March of Dimes does not endorse specific brands or products.

See also: Healthy eating during pregnancy, Vitamins and pregnancy

Most common questions

How much weight should I gain during my pregnancy?

The exact amount of weight you need to gain depends on how much you weigh before pregnancy and your Body Mass Index (BMI). Below are some guidelines, but talk to your health provider about your specific pregnancy weight gain goals.

If you began pregnancy at a healthy weight, you should gain 25 to 35 pounds over the 9 months. If you gain between 1 and about 4 ½ pounds in the first trimester, you should put on about 1 pound every week in the second and third trimesters.

If you began pregnancy underweight, you should probably gain about 28 to 40 pounds. If you gain between 1 and about 4 ½ pounds in the first trimester, try to gain slightly over a pound a week in the second and third trimesters.
If you began pregnancy overweight, you should gain only 15 to 25 pounds over the 9 months. If you gain between 1 and about 4 ½ pounds in the first trimester, you should put on slightly over ½ pound every week in the second and third trimesters. While you don't want to gain too much weight, never try to lose weight during pregnancy because that could harm your baby.

If you were obese (with a BMI over 30) at the start of your pregnancy, you should gain only 11 to 20 pounds over the 9 months. If you gain between 1 and about 4 ½ pounds in the first trimester, aim for gaining slightly under ½ pound every week in the second and third trimesters.

Is it safe to eat cold cuts when I'm pregnant?

It's not safe for pregnant women to eat deli meats (such as ham, turkey, salami and bologna) or hot dogs unless the food has been thoroughly heated and is steaming hot. These foods can cause a form of food poisoning called listeriosis and is caused by bacteria. Heating deli meats until steaming hot will kill the bacteria if it's present.

Listeriosis is especially dangerous during pregnancy. Most people don't get sick when they eat food contaminated with listeria. But healthy pregnant women are more likely than other healthy adults to get listeriosis and are more likely to become dangerously ill from it.

The flu-like symptoms of listeriosis can sometimes advance to potentially life-threatening meningitis (infection of the membranes covering the brain, with symptoms such as severe headache and stiff neck) and blood infection. Contact your health care provider if you're pregnant and you develop any of these symptoms.

Is it safe to eat fish raw or seared during pregnancy?

You should avoid all raw or seared fish when you're pregnant. (Seared fish are typically not fully cooked throughout.) Raw fish, including sushi and sashimi, and undercooked finfish and shellfish (including oysters, clams, mussels and scallops) are more likely to contain parasites or bacteria than cooked fish. 

Avoid swordfish, shark, king mackerel and tile fish, even when cooked. These fish have more mercury than other fish. Mercury can be transferred to your growing baby and cause serious health problems. Stay away from game fish, too, until you check its safety with your local health department. A game fish is any fish caught for sport, such as trout and bass.

The USDA recommends that pregnant women limit their fish consumption to 12 ounces of a variety of cooked fish per week.

©2013 March of Dimes Foundation. The March of Dimes is a non-profit organization recognized as tax-exempt under Internal Revenue Code section 501(c)(3).