[Hot Science] Maternal omega-3 fatty acid status and early preterm birth

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General Nutrition Neonatology Obstetrics / Gynaecology Nutrition & Disease Management
[Hot Science] Maternal omega-3 fatty acid status and early preterm birth

This is the first study to investigate if a low plasma omega-3 fatty acid status during pregnancy is associated with an elevated risk of early preterm birth, < 34 weeks of gestation.


  • Preterm birth (< 37 gestational weeks) is a leading cause of mortality in infancy and early childhood whereas infants born in earlier preterm period experience a much higher rates of prematurity-related complications
  • Meta-analyses of available randomized controlled trials have implicated the potential role of higher long chain n-3 fatty acid intake on longer mean gestational length
  • The study aims to examine if a low plasma level of long chain n-3 fatty acids during pregnancy is related to a higher risk of subsequent early preterm birth (< 34 gestational weeks)

Study Design

  • A case-control study nested in a national prospective population-based study in Denmark, Danish National Birth Cohort (DNBC)


  • Early preterm cases and random controls were identified from the cohort,
    • 376 early preterm cases (< 34 gestational weeks, excluding preeclampsia cases)
    • 348 random control cases


  • Plasma EPA + DHA level (% of total fatty acids) were measured twice,
    • Gestational week 9 (early pregnancy)
    • Gestational week 25 (mid-pregnancy)
  • Associations between EPA + DHA level and early preterm risk were speculated by logistic regression with adjustments to various factors including age, height, pre-pregnancy BMI and parity, etc


Key Findings

  • Early preterm risk varied with different factors that tended to be related with EPA + DHA level recorded in both time points (gestational weeks 9 and 25),
    • Age
    • Parity
    • Pre-pregnancy BMI
    • Daily smoking
  • Mena plasma EPA +DHA levels (% of total fatty acids) in the two groups at different time points,


Early Preterm Group

Random Control Group

Gestational week 9



Gestational week 25




  • A strong, significant and non-linear association (p < 0.0001) between increased risk of early preterm and low EPA + DHA level (< 2% of total fatty acids)
  • Women with EPA + DHA level in the lowest quintile (< 1.6% of total fatty acids) exhibited 10.27 times higher odds of early preterm birth (95% confidence interval 6.80 to 15.79, p < 0.0001)
  • The spine model indicated a threshold effect at EPA + DHA levels between 2.0% to 2.5% and a steep increase in risk at low levels that then flattened quickly at higher levels
  • EPA + DHA status recorded at gestational week 25 tended to be more strongly related with the risk of early preterm birth versus those at gestational week 9


  • Low EPA + DHA status during pregnancy is a strong risk factor for early preterm birth

Link to the full article: https://www.ebiomedicine.com/article/S2352-3964(18)30252-4/pdf



Olsen  SF, Halldorsson TI, Thorne-Lyman AL, Strom M, Gortz S, Granstrom C, Nielsen PH, Wohlfahrt J, Lykke JA, Langhoff-Roos J, Cohen AS, Furtado JD, Giovannucci EL, Zhou W. Plasma concentrations of long chain n-3 fatty acids in early and mid-pregnancy and risk of early preterm birth. EBioMedicine 2018. https://doi.org/10.1016/j.ebiom.2018.07.009.