Objective Women in labor with epidural analgesia are prone to fever. Intrapartum fever is associated with neonatal infection. Whether fever in women with an epidural reflects mere hyperthermia, inflammation or infection is debated. To search for a safe temperature cut-off, we hypothesized that low grade (<38.5°C) fever associated with epidural analgesia during labour caused no excess risk of neonatal infection compared with no fever.
Methods A cohort study of 17,542 women with intended vaginal delivery and singleton, term, liveborn babies, Aarhus University Hospital, Denmark. Temperature was measured if shivering, malaise or fetal tachycardia and prior to epidural analgesia. Neonatal sepsis was defined by ICD10 codes given at discharge by senior specialists in neonatology. Potential confounders considered were; duration of rupture of membranes, parity, maternal characteristics, and induction.
Results A total of 3,533 women (20%) received an intrapartum epidural, 11% of these developed fever whereas 0.6% of women with no epidural had fever. The risk of neonatal sepsis with epidural and fever was 4 fold increased (OR = 3.7; 95% CI 2.5 to 5.9), while the risk of sepsis with fever without epidural was much higher (OR = 16.7; 95% CI 9.6 to 29). Neonatal infection risk in women with an epidural increased with temperature; in babies of afebrile women with an epidural the risk was 1.9% with increasing risk from low grade to high grade fever from 4.9% to 10%.
Conclusion It is impossible to identify a safe cut-off for intrapartum temperature in women with epidural analgesia below which an excess risk of newborn infection could be neglected.