Objectives: The risk factors for prematurity are multifactorial and include low omega-3 status. Omega-3 supplementation in pregnancy has been found to reduce prematurity risk, particularly among women with low omega-3 levels. This study aimed to identify maternal characteristics that predict whether women with a singleton pregnancy will benefit from omega-3 supplementation to reduce their risk of prematurity.
Design: Exploratory analyses of a multicentre, double-blind randomised trial.
Setting: 6 tertiary care centres in four states in Australia.
Participants: 5328 singleton pregnancies in 5305 women recruited before 20 weeks of gestation.
Interventions: Fish oil capsules containing 900 mg omega-3 long-chain polyunsaturated fatty acids per day versus vegetable oil capsules consumed from enrolment until 34 weeks' gestation.
Outcome measures: Early preterm birth (EPTB, <34 weeks' gestation) and preterm birth (PTB, <37 weeks' gestation) analysed using logistic regression models with interactions between treatment group and a range of maternal biological, clinical and demographic characteristics.
Results: Omega-3 supplementation reduced the odds of EPTB for women with low total omega-3 status in early pregnancy (OR=0.30, 95% CI 0.10-0.93). No additional maternal characteristics influenced whether omega-3 supplementation reduced the odds of EPTB. For PTB, women were more likely to benefit from omega-3 supplementation if they were multiparous (OR=0.65, 95% CI 0.49-0.87) or avoided alcohol in the lead up to pregnancy (OR=0.62, 95% CI 0.45-0.86).
Conclusions: Our results support previous findings that women with low total omega-3 levels in early pregnancy are most likely to benefit from taking omega-3 supplements to reduce their risk of EPTB. Understanding how other maternal characteristics influence the effectiveness of omega-3 supplementation on reducing PTB requires further investigation.
Trial registration number: ACTRN12613001142729.
Keywords: NEONATOLOGY; NUTRITION & DIETETICS; OBSTETRICS; PUBLIC HEALTH.
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