significance remain uncertain. We examined the association between plasma fatty acids quantified in pregnancy
and subsequent risk of early preterm birth.
Methods: In a case-control design nested in the Danish National Birth Cohort, we identified 376 early preterm
cases (acid plus docosahexaenoic acid (EPA+DHA% of total fatty acids), were measured twice in pregnancy, at gestation
weeks 9 and 25 (medians). Odds ratios and 95% confidence intervals (CI's) for associations between EPA+DHA
and early preterm risk were estimated by logistic regression, adjusted for the woman's age, height, pre-pregnancy BMI, parity, smoking, and socioeconomic factors. Hypotheses and analytical plan were defined and archived a priori.
Findings: Analysis using restricted cubic splines of the mean of 1st and 2nd sample measurements showed a
strong and significant non-linear association (p < 0.0001) in which the risk of early preterm birth steeply increased when EPA+DHA concentrations were lower than 2% and flattened out at higher levels. Women in the
lowest quintile (EPA+DHA < 1.6%) had 10.27 times (95% confidence interval 6.80–15.79, p < 0.0001) increased
risk, and women in the second lowest quintile had 2.86 (95% CI 1.79–4.59, p < 0.0001) times increased risk,
when compared to women in the three aggregated highest quintiles (EPA+DHA ≥ 1.8%).
Interpretation: Low plasma concentration of EPA and DHA during pregnancy is a strong risk factor for subsequent
early preterm birth in Danish women.
- Danish National Birth Cohort
- Early preterm birth
- Long chained n-3 fatty acids
- Prospective study