Predictors of compliance with higher dose omega-3 fatty acid supplementation during pregnancy and implications for the risk of prematurity: exploratory analysis of the ORIP randomised trial

BackgroundIntention-to-treat analyses of the Omega‐3 to Reduce the Incidence of Prematurity (ORIP) trial found that omega-3 (n-3) fatty acid supplementation reduces the risk of prematurity in the subgroup of women with a singleton pregnancy and low n-3 status early in pregnancy, but not overall. However, results may have been influenced by less-than-optimal compliance.ObjectivesTo identify predictors of compliance with n-3 supplementation and determine treatment effects among compliers.DesignExploratory analyses of a multicentre-blinded randomised trial.Setting6 tertiary care centres in Australia.Participants5328 singleton pregnancies.InterventionsDaily capsules containing 900 mg n-3 long-chain polyunsaturated fatty acids or vegetable oil, consumed from before 20 weeks gestation until 34 weeks gestation.Outcome measuresEarly preterm (