P3 - Omega-3 to Reduce the Incidence of Preterm Birth – from bench to bedside

Abstract

Globally, preterm birth is the leading cause of death in children under 5 years. Around two thirds of preterm births occur without known biological cause, therefore prevention strategies are critical. Increased intake of omega-3 long chain polyunsaturated fatty acids (LCPUFAs) during pregnancy has been linked to increased length of gestation and reduction of preterm birth. We aimed to determine the effect of supplementing the diets of pregnant women with omega-3 LCPUFA on the incidence of early preterm birth (<34 weeks’ gestation). A national, multicentre, double blind, parallel group, randomised controlled trial. 5544 pregnant women were randomised to daily capsules containing 900 mg omega-3 (800 mg docosahexaenoic acid and 100 mg eicosapentaenoic acid) or vegetable oil (control) from <20 weeks until 34 weeks’ gestation. Our primary outcome was the incidence of early preterm birth. Overall, there was no significant difference in the incidence of early preterm birth in the omega-3 group compared to control. However, exploratory analyses (n=5070 singleton pregnancies) found the risk of early preterm birth in women with low omega-3 status at enrolment was significantly reduced by 77% with omega-3 supplementation (RR = 0.23, 95% CI 0.07-0.79). In contrast, women with replete omega-3 status were already at lower risk of early birth and supplementation increased their risk of early preterm birth (RR = 2.27, 95% CI 1.13-4.58). Women with low omega-3 status benefit most from omega-3 supplementation to reduce their risk of early preterm birth. The 2018 Cochrane review including >70 trials supports our findings reporting a 42% reduction in early preterm birth. The 2021 Australian Pregnancy Care Guidelines now contain a new evidence-based recommendation to advise omega-3 supplementation to reduce the risk of prematurity for women who are low in omega-3. A state-wide implementation and evaluation of the guideline is underway in South Australia.