Objective: To determine whether n-3 fatty acid (EPA/DCHA) prophylaxis is beneficial in high risk pregnancies.
Design: A randomised, double blind, placebo controlled trial.
Setting: Antenatal clinic of St James's University Hospital, Leeds.
Subjects: Two hundred and thirty-three pregnant women at high risk of developing proteinuric or nonproteinuric pregnancy induced hypertension or asymmetrical intrauterine growth retardation.
Intervention: Active treatment was 2.7 g of MaxEpa daily (1.62 g of eicosapentaenoic acid and 1.08 g of docosahexaenoic acid). Placebo were matching air-filled capsules.
Main outcome measures: Occurrence of proteinuric, nonproteinuric pregnancy induced hypertension or birthweight < 3rd centile.
Results: There was no difference in an intention to treat analysis between the placebo and active treatment groups for occurrence of proteinuric pregnancy induced hypertension (relative risk (RR) = 0.88; 95% CI 0.47-1.66), nonproteinuric pregnancy induced hypertension (RR = 0.89; 95% CI 0.48-1.64), birthweight < 3rd centile (RR = 0.89; 95% CI 0.48-1.64), or the duration of pregnancy (difference of mean durations = 0.1 days; 95% CI -4.8 to 4.9 days). Analyses stratified by use of tobacco, and analyses excluding known major protocol violators gave essentially identical results.
Conclusion: There is no evidence from this study for any useful effect of fish oil supplementation for women at high risk of adverse outcomes from a pregnancy, but a small protective effect remains a possibility.