expert opinion

Why is DHA Omega-3 Such an Important Nutrient During Pregnancy?

Gregory Ward, M.D.

February 21, 2019

The first 1,000 days of a child’s development starts from the moment of conception until his or her second birthday. This time provides a unique window of opportunity for parents to positively influence their child’s long term physical and mental health and to ensure that their child reaches their maximum potential.

The latter part of pregnancy and the early years are the greatest period of brain growth. DHA is a major structural fat in the brain and the fetus and infant’s brain needs to accumulate large amounts of DHA as it develops. In 2009 a study by Kannass et al. showed that infants born to mothers with higher blood levels of DHA at delivery had advanced levels of attention span well into their second year of life. (1) The recommended intake for pregnant women is 500 mg per day either from dietary sources such as oily fish or from DHA fortified foods, beverages and dietary supplements.

Recommended Intake

The 2018 Cochrane Review found high-quality evidence that supplementation with long-chain omega-3 fats during pregnancy reduced the risk of having a premature baby (less than 37 weeks) by 11 percent (25 trials:10,184 participants) and reduced the risk of early preterm birth (less than 34 weeks) by 42 percent (9 trials: 5,204 participants) compared with no long-chain omega-3 supplementation. In light of these findings, the authors concluded that a dose of 500-1,000 mgs of long-chain omega-3 fats, DHA and EPA, daily with a minimum addition of 500 mg of DHA per day was the most effective. (2)

Further evidence of the vital importance of the mother’s DHA status in pregnancy on infant brain development was provided by a Norwegian study published in May 2018. (3)

To investigate the importance of DHA in the fetus and infants’ brain growth and development they studied the association between the DHA status of pregnant women and the problem-solving skills of a healthy term-born infant.

They measured the mother’s DHA blood levels at week 28 of pregnancy and three months after delivery and correlated this with the infant’s fatty acid blood levels at three, six and 12 months of age and the infants’ problem-solving skills at six and 12 months.

They found that the mother’s DHA status in pregnancy was positively associated with the infants problem-solving skills at 12 months even after taking into account confounding factors such as the level of maternal education, which they used as a surrogate for socio-economic status. They also found that the infants’ DHA status at three months was positively associated with infants’ problem-solving skills at 12 months.

They concluded that the results reinforced the importance of pregnant and lactating women having a satisfactory DHA intake from either their diet or other sources rich in DHA.

The Norwegian study reinforced the beneficial findings found by Kannass et al in 2009. The study explained that to understand why an adequate dietary DHA intake is so important we need to look at the development of the fetal and infant brain which undergoes a rapid growth spurt during the last 14 weeks of pregnancy and during the first year of life. They explain that both DHA and the Omega-6 PUFA arachidonic acid (ARA) are important for the development of visual and brain tissues and subsequent motor and cognitive development. (4,5)

Therefore, an adequate intake of DHA and ARA is important for pregnant and lactating women and infants. Modern diets contain adequate amounts of ARA but obtaining the optimal intake of DHA is more challenging.

Other Benefits of DHA Omega-3

Other potential benefits of DHA in pregnancy have also been studied. Over 30 years ago scientists observed that women living in the Faroe Islands, where diets are typically high in omega-3 rich seafood had longer pregnancies and babies with higher birth weights than those living in mainland Denmark. (6) A recent large-scale review of several studies concluded that omega-3 PUFAs reduce the risk of premature birth. (7) To explore this further the Adore trial, a 2017 American study, is assessing the impact of DHA on reducing preterm birth. (8) As inflammation is a well-known cause of preterm labor the authors postulate that DHA may be effective because of its anti-inflammatory properties.

A further pregnancy related potential role of omega-3 PUFAs is their role in helping to manage perinatal depression as outlined by Lin et al in their 2017 meta-analysis (9). Perinatal depression is increasingly recognized as having an adverse effect on both the mother and baby and this study lends further weight to the necessity of having an adequate intake of DHA during pregnancy and lactation.

DHA is vital to ensure a healthy pregnancy by supporting optimal maternal and infant health. The current recommendation is that pregnant women consume at least 500mg of DHA omega-3 per day. However, only a small proportion of women consume the recommended level and if you are already pregnant or are trying to conceive make sure you eat plenty of fruit and vegetables, healthy fats and proteins and speak to your patients about taking daily supplements that include DHA to ensure they get sufficient quantities of the nutrients that mother and baby need.

Read more about the landmark Cochrane Review published in 2018.

References

  1. Kannass, K.N., Colombo, J. and Carlson, S.E., 2009. Maternal DHA levels and toddler free-play attention. Developmental neuropsychology, 34(2), pp.159-174.
  2. Middlleton et al., 2018. Cochrane Review
  3. Braarud, H.C., Markhus, M.W., Skotheim, S., Stormark, K.M., Frøyland, L., Graff, I.E. and Kjellevold, M., 2018. Maternal DHA Status during Pregnancy Has a Positive Impact on Infant Problem Solving: A Norwegian Prospective Observation Study. Nutrients, 10(5).
  4. Lauritzen, L.A., Hansen, H.S., Jørgensen, M.H. and Michaelsen, K.F., 2001. The essentiality of long chain n-3 fatty acids in relation to development and function of the brain and retina. Progress in lipid research, 40(1), pp.1-94.
  5. Julvez, J., Méndez, M., Fernandez-Barres, S., Romaguera, D., Vioque, J., Llop, S., Ibarluzea, J., Guxens, M., Avella-Garcia, C., Tardón, A. and Riaño, I., 2016. Maternal consumption of seafood in pregnancy and child neuropsychological development: a longitudinal study based on a population with high consumption levels. American journal of epidemiology, 183(3), pp.169-182.
  6. Olsen, S.F. and Joensen, H.D., 1985. High liveborn birth weights in the Faroes: a comparison between birth weights in the Faroes and in Denmark. Journal of Epidemiology & Community Health, 39(1), pp.27-32.
  7. Kar, S., Wong, M., Rogozinska, E. and Thangaratinam, S., 2016. Effects of omega-3 fatty acids in prevention of early preterm delivery: a systematic review and meta-analysis of randomized
    studies. European Journal of Obstetrics & Gynecology and Reproductive Biology, 198, pp.40-46.
  8. Carlson, S.E., Gajewski, B.J., Valentine, C.J., Rogers, L.K., Weiner, C.P., DeFranco, E.A. and Buhimschi, C.S., 2017. Assessment of DHA on reducing early preterm birth: the ADORE randomized controlled trial protocol. BMC pregnancy and childbirth, 17(1), p.62.
  9. Lin, P., Chang, C.H., Chong, M.F.F., Chen, H. and Su, K.P., 2017. Polyunsaturated fatty acids in perinatal depression: a systematic review and meta-analysis. Biological Psychiatry, 82(8), pp.560-569.