• maternal prenatal depression;
  • maternal diet;
  • omega-3 fatty acids;
  • fish;
  • maternal smoking;
  • marital status;
  • environment–environment interactions


An inverse association between depression and the n-3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), primarily obtained from fish consumption, is observed in both observational and experimental research and is biologically plausible. Study objectives were to examine whether prenatal depressive symptoms were associated with lower intakes of fish or EPA+DHA. Pregnant women (n = 2394) completed a telephone interview between 10 and 22 weeks' gestation in London, Ontario, 2002–05. Depressive symptoms were measured using the Center for Epidemiologic Studies – Depression Scale (CES-D). Intakes of fish and EPA+DHA were measured using a validated food-frequency questionnaire. Sequential multiple regression was used to examine associations of depressive symptoms with intake of fish and EPA+DHA, respectively, while controlling for sociodemographic, health and lifestyle variables.

The mean CES-D score was 9.9 (SD 8.0). Intake of EPA+DHA was dichotomised at the median value of 85 mg/day. Fish consumption and intake of EPA+DHA were not associated with prenatal depressive symptoms after adjustment for confounders; however, depressive symptoms were significantly higher for lower intakes of EPA+DHA among current smokers and women of single/separated/divorced marital status. The adjusted difference in CES-D scores between intake categories of EPA+DHA was −2.4 [95% CI −4.2, −0.4] for current smokers and −2.8 [95% CI −5.2, −0.4] for women of single marital status. Although pregnant women may be at risk for low concentrations of EPA and DHA, an association between low intakes of EPA+DHA and increased depressive symptoms was only observed among current smokers and women of single marital status.