Omega-3 related oxylipins in pregnancy and their associations with gestational age and preterm birth: A systematic review of observational studies and randomised controlled trials.

BACKGROUND: Maternal omega-3 fatty acid status can influence gestational length, with low omega-3 status associated with increased preterm birth risk. However, the underlying mechanisms remain unclear. Oxylipin derivatives are plausible mediators of gestational timing and preterm birth risk. This review evaluates whether studies combining an omega-3 exposure or intervention with oxylipin profiling provide mechanistic insights into gestational length or preterm birth risk. METHODS: Randomised controlled trials (RCTs) and observational studies in pregnant women that included an omega-3 intervention or recorded omega-3 exposure, with oxylipins quantified by liquid chromatography coupled with mass spectrometry (LC-MS), were systematically reviewed. RESULTS: Two studies were identified that included an omega-3 intervention and quantification of oxylipins by LC-MS, both nested within the same parent trials. One study examined associations between oxylipins and gestational outcomes and reported that specific lipoxygenase derived oxylipins measured in early pregnancy were associated with higher risk of spontaneous preterm birth. The other study evaluated changes in oxylipin profiles in response to omega-3 supplementation but did not assess associations with gestational length or preterm birth. CONCLUSIONS: Available evidence is insufficient to clarify relationships between omega-3 status, preterm birth or gestational length. Limited findings suggest that select oxylipins may be associated with spontaneous preterm birth risk, but evidence remains hypothesis generating. Further well-designed studies using standardised LC-MS methods and broader oxylipin profiling are needed.