biostudies-literatureEPIFEVER-2 investigatorsNational Institute for Health Research (NIHR)134-140https://www.ebi.ac.uk/biostudies/studies/S-EPMC12226748biostudies-literatureUnknown135(1)<h4>Background</h4>Genetically predicted higher levels of the anti-inflammatory cytokine interleukin-1 receptor antagonist (IL1-Ra) might reduce the risk of developing epidural-related maternal fever, a phenomenon that occurs exclusively in women having epidural analgesia in labour. We hypothesised that in women having epidural analgesia, the absence of specific alleles that lower circulating levels of IL1-Ra would be associated with the development of epidural-related maternal fever, administration of intrapartum antibiotics, or both.<h4>Methods</h4>We prospectively enrolled women ≥18 yr of age receiving epidural analgesia during labour, excluding those with pre-existing fever, antibiotic therapy, or immunodeficiency. Allele scores were constructed from genotyping the C-allele frequency aBritish journal of anaesthesiaInterleukin-1 receptor antagonist polymorphisms in women receiving epidural analgesia who develop maternal intrapartum fever: a prospective, multicentre Mendelian randomised study.PMC12226748NIHR300097Thompson CPatel ARodriguez Sierra EPBrunnen DPatrick ARaja JWilson VPhull MStephenson LArumugaum ARazzaque MWilson MWray STanqueray TFrowd RTripurneni VBlake HWeist SMartin TLeary RCanclini LWikner MKwok SKennedy NNoakes IDe Freixo LDavid ALAchempong YPinder ASarmiento LBorg LXBerger PNoblett JLongbottom RCarey ANicklin ABegum SAl-Maiyah FHoodless STsun JSousi EBruce-Hickman KMak KGeorge DKim JBarrett AOdor PCosta AVValori LBourke MUsman NSharp TAli AAbbott TEFHoe MNewth OCoulter CGutierrez Del Arroyo ASmith CWaspe JWong RKhan ASingh ACiechanowicz SWarrington AChapman AMeroz MRVerma PStretch BAli JQuereshi NCollins EFolorunsho MEiben PDias PPapoutsos CVishwanathan ASritharan PWeber VDas APalfreeman CMazzoli IBramley PBlack REPIFEVER-2 investigatorsAckland GfalseInterleukin-1 receptor antagonist polymorphisms in women receiving epidural analgesia who develop maternal intrapartum fever: a prospective, multicentre Mendelian randomised study.<h4>Background</h4>Genetically predicted higher levels of the anti-inflammatory cytokine interleukin-1 receptor antagonist (IL1-Ra) might reduce the risk of developing epidural-related maternal fever, a phenomenon that occurs exclusively in women having epidural analgesia in labour. We hypothesised that in women having epidural analgesia, the absence of specific alleles that lower circulating levels of IL1-Ra would be associated with the development of epidural-related maternal fever, administration of intrapartum antibiotics, or both.<h4>Methods</h4>We prospectively enrolled women ≥18 yr of age receiving epidural analgesia during labour, excluding those with pre-existing fever, antibiotic therapy, or immunodeficiency. Allele scores were constructed from genotyping the C-allele frequency a2025-01-01T00:00:00Z2025 Jul2026-05-26T20:09:33.601Z2026-05-26T03:06:33.109ZS-EPMC122267484036868510.1016/j.bja.2025.03.037