The Importance of Omega-3 Intake During Pregnancy

Omega-3 fatty acids are essential and can only be obtained from the diet. The requirements during pregnancy have not been established, but likely exceed that of a nonpregnant state. Omega-3 fatty acids are critical for fetal neurodevelopment and may be important for the timing of gestation and birth weight as well. Most pregnant women likely do not get enough omega-3 fatty acids because the major dietary source, seafood, is restricted to 2 servings a week. For pregnant women to obtain adequate omega-3 fatty acids, a variety of sources should be consumed: vegetable oils, at two low-mercury fish servings a week, and supplements (preferably high in fish oil derived docosahexaenoic acid DHA).
 

DHA concentration is high in retinal and brain membrane phospholipids, and it is involved in visual and neural function and neurotransmitter metabolism¹. During the last trimester, the fetus accrues about 50 to 70 mg a day of 1 omega-3 fatty acid, DHA². Both maternal DHA intake and circulating DHA concentrations are important determinants of fetal blood concentrations of DHA³. Babies accumulate  DHA into the central nervous system up until about 18 months of age^4. 
 

Unfortunately, it is impossible for pregnant women to meet their omega-3 fatty acid requirements from omega-3-rich vegetable oils and 2 servings of seafood a week. Two servings of fish per week only provide about 100 to 250 mg per day of omega-3 fatty acids, of which 50 to 100 mg is from DHA; plant-based oils supply insignificant amounts of eicosapentaenoic acid (EPA) and no DHA. During pregnancy, the dietary goal for omega-3 fatty acids is a minimum 650 mg, of which 300 is DHA⁵. Thus, in order make up the omega-3 fatty acid deficit in the diet, pregnant women are left with essentially 2 choices: fish oil supplements supplying EPA and DHA, or algae-derived DHA. Specifically, depending upon the omega-3 content of the seafood consumed during the week, each day pregnant women would need an additional 400 to 550 mg of omega-3 PUFAs (EPA and DHA), of which at least 225 mg should be DHA.

There is little doubt that pregnant women need at least as many omega- 3 fatty acids as nonpregnant women, and likely need more DHA⁶. The recommendations for dietary omega-3 fatty acids should be adopted at the onset of pregnancy, but there may be benefits for all women who are considering becoming pregnant. Given concerns for mercury toxicity with overconsumption of certain fish, pregnant women will likely be required to consume omega-3 fatty acids from two servings of seafood per week, and daily omega-3 fatty acid supplements containing EPA and DHA or DHA alone. Intake of omega-6-rich oils found in sunflower, corn, and cottonseed oils should be minimized because they are converted to substrates that compete with omega-3. Pregnant women should reduce their intake of these oils and consume oils rich in omega-3 fatty acids derived from marine sources.

1. Taking DHA during pregnancy may reduce the risk of preterm birth⁷ and promote healthy  brain and eye development. It can also lead to more lean body mass in children at age five and improve sustained attention at preschool age.
 

2. DHA is utilized rapidly by the baby’s brain and retina during pregnancy. Omega-3 fatty acids, especially DHA, are building blocks of the baby’s brain and retina.  As accumulation of DHA continues until age two, DHA intake is essential during breastfeeding and formula feeding.

3. Consuming omega-3 during pregnancy may have a benefit for maternal mental well-being. Observational data show a connection between low intake of DHA and EPA and a higher risk of depression.

4. Although many factors play a role, DHA supplementation during pregnancy may positively impact a child’s risk of Childhood obesity. A 2018 study published in the American Journal of Clinical Nutrition reported that moms who took 600 mg of DHA during pregnancy had children with more fat-free body mass at age five compared to the placebo group.
 

5. A small study of infants living in urban, low-income environments showed better one-minute Apgar scores, higher birth weight, and better infant response to stress when moms received DHA supplementation.

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4. Birch EE, Castaneda YS, Wheaton DH, et al. Visual maturation of term infants fed long-chain polyunsaturated fatty acid-supplemented or control formula for 12 mo. Am J Clin Nutr. 2005;81:871–879. [PubMed]
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7. Philippa Middleton, Judith C Gomersall, Jacqueline F Gould, Emily Shepherd, Sjurdur F Olsen, Maria Makrides. Omega‐3 fatty acid addition during pregnancy. Nov 2018. 10.1002/14651858.CD003402.pub3.