Interleukin-1 Receptor Antagonist Polymorphisms in Women Receiving Epidural Analgesia Who Develop Maternal Intrapartum Fever: A Prospective, Multicentre Mendelian Randomised Study

( Br J Anaesth. 2025;135:134-140 doi: 10.1016/j.bja.2025.03.037) The EPIFEVER-2 study was an extensive, prospective, multicenter Mendelian randomization study exploring whether genetic variants influencing interleukin-1 receptor antagonist (IL-1Ra) levels affect the risk of maternal fever during labor in women receiving epidural analgesia (LEA). Since epidural-related maternal fever (ERMF) occurs in roughly 20% of laboring women, researchers hypothesized that higher genetically predicted levels of IL-1Ra, a natural anti-inflammatory cytokine, might protect against fever and the associated need for intrapartum antibiotics.