Importance of Omega-3 DHA for Pregnancy

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Getting the proper nutrients is important for moms-to-be, but do you know why omega-3 DHA is important during pregnancy, where to find it and how much you need? Read on!

Omega-3 DHA is one of three major omega-3 fatty acids essential to human health that we need to get from our diet:

1. Alpha-linolenic acid (ALA)

2. Eicosapentaenoic acid (EPA)

3. Docosahexaenoic acid (DHA)

Omega-3 fatty acids are healthy fats that play important structural and functional components of cell membranes. They also have a number of other important functions such as supporting your heart, brain, eye and immune system heath.  

Common food sources: plant foods such as flaxseed/oil, canola oil, walnuts, hempseeds, chia seeds

Our bodies can convert this short chain plant-based omega-3 to the longer chain omega-3s EPA and DHA, however, the metabolic conversion of ALA is highly variable between individuals and quite limited.  Due to this, experts recommend consuming foods rich in omega-3 EPA and DHA directly and if needed, consider supplementing, since many of the health benefits associated with omega-3 fatty acids are due to the longer chain omega-3s EPA and DHA.

Common food sources: fish and seafood with predominant sources being fatty fish such as salmon, mackerel, herring and trout. 

Omega-3s can also be found in fortified or enhanced food products in the marketplace such as eggs and dairy.

Fish oil supplements which provide EPA and DHA are also available. Algae oil is another option as it’s a vegetarian source and typically provides only DHA. As always, if you’re considering a supplement speak with your healthcare professional first to determine if a supplement is right for you.

DHA contributes to normal brain and eye development of the fetus and breastfed infants. DHA is especially important during the period of rapid brain and nervous system development, which takes place during the last trimester to age two.  DHA accumulates rapidly in the brain and retina during the later part of gestation and early postnatal life. Research has also shown, adequate DHA can help reduce the risk preterm birth (<37 weeks) and early preterm birth (<34 weeks).  

During pregnancy, DHA is transferred from the mother across the placenta and accumulates in the growing fetal brain and other tissues. After birth, DHA is transferred through breast milk. Dietary DHA contributes to the mother’s DHA status, and pregnant and breastfeeding women with higher intakes of DHA transfer more DHA to their fetus, and supply more DHA in their breast milk.

The Institute of Medicine (IOM) in collaboration with Health Canada sets nutrient standards in the Dietary Reference Intakes. At this time, the IOM and Health Canada have not established a dietary recommendation for DHA. However, dietary recommendations for DHA have been established by some other international organizations.

The World Association of Perinatal Medicine recommends pregnant and breastfeeding women should aim to achieve an average daily intake of at least 200mg DHA.

While fish is a good source of omega-3 fatty acids, and can be part of a healthy eating pattern, Health Canada has issued specific advice for women who are or may become pregnant as well as breastfeeding women to minimize mercury exposure from fish. It’s important to minimize mercury exposure since mercury can affect the developing brain.

Fish advice:

  • limit consumption of fresh/frozen tuna, shark, swordfish, escolar, marlin, and orange roughy.  You can eat 150 g per month of these fish species combined. 
  • you may consume up to 300g a week of canned albacore (white) tuna. This is equivalent to about two 170-g cans of albacore tuna per week.* 

*Note: this advice does not apply to canned “light” tuna, which has less mercury than canned “white” albacore tuna

Health Canada recommends choosing fish and shellfish that contain higher levels of DHA + EPA and are also low in mercury which include: anchovy, capelin, char, hake, herring, Atlantic mackerel, mullet, pollock (Boston bluefish), salmon, smelt, rainbow trout, lake whitefish, blue crab, shrimp, clam, mussel and oyster.

By making informed choices about what types of fish are consumed and how often, mercury exposure from fish can be minimized while the health benefits associated with eating fish continue to be gained.

For further information: Mercury in Fish. Consumption Advice: Making Informed Choices about Fish

Food Content per 75g (cooked)DHA (mg)EPA (mg)
Salmon, Atlantic, farmed1093518
Sockeye salmon, canned835554
Rainbow trout, farmed615250
Jack mackerel, canned597326
Coho salmon, wild494301
Rainbow trout, wild390351
Halibut, Greenland (Turbot)378506
Pollock (Boston bluefish)33868
Arctic char300375
Omega-3 enriched eggs (2 eggs)150n/a
Sole194182
Light tuna, canned16735
Cod1163
Shrimp108128
Tilapia984
Chicken, dark meat388
Eggs283
Chicken, breast94
Pork00
Note: Meat from ruminants (cows, lamb, goats) is naturally low in DHA
  • DHA is important for normal fetal brain and eye development, as well as helping reduce the risk of preterm birth (<37 weeks) and early preterm birth (<34 weeks)
  • It is important that maternal DHA stores are adequate throughout pregnancy as the fetus relies on maternal sources of DHA
  • This remains important at delivery as DHA in breast milk is important for proper infant development
  • Dietary intake of DHA during pregnancy and lactation is an important way to address the fetal and neonatal need for DHA, as well as the maternal need
  • Various organizations recommend pregnant and breastfeeding women should aim to achieve an average daily intake of at least 200mg DHA
  • Health Canada recommends choosing fish and shellfish that contain higher levels of DHA + EPA and are also low in mercury. By making informed choices about what types of fish are consumed and how often, mercury exposure from fish can be minimized while the health benefits associated with eating fish continue to be gained.
  • As always, if you’re considering a supplement speak with your healthcare professional first to determine if a supplement containing DHA is right for you.

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