The Impact of Local Anesthetic Solution Temperature on Epidural-related Maternal Fever

Background: Maternal fever during labor is common, with an incidence of about 33%, often due to infection, epidural analgesia, or environmental factors. Multiple studies have indicated that the rate of intrapartum fever in women who receive epidural analgesia is approximately between 15% and 25%. After epidural analgesia, the risk of maternal fever significantly increases, a condition known as Epidural-Related Maternal Fever (ERMF). ERMF not only increases unnecessary antibiotic use but may also lead to unplanned cesarean sections, increased perinatal bleeding, and other complications. Moreover, any cause of intrapartum fever, including ERMF, can increase the incidence of neonatal brain injury by approximately 2.79 times. With the popularization of the concept of painless childbirth, ERMF has increasingly attracted people's attention. Despite being identified in 1989, the pathogenesis of ERMF remains unclear, with several mechanisms proposed, including infection, sympathetic blockade, and non-infectious inflammation induced by local anesthetics. Methods: This is a prospective randomized controlled study with 424 participants receiving epidural analgesia at two hospitals from October 2024 to October 2027. Participants will be randomly assigned to receive either 37°C or 23°C local anesthetic solutions. The study will measure maternal fever rates, the time for pain scores to decrease, and peripheral perfusion index at various intervals. Maternal and neonatal outcomes, including antibiotic usage, sepsis incidence, and Apgar scores, will be recorded. Possible Conclusions: The study aims to determine if the temperature of local anesthetics influences the incidence of ERMF. It also seeks to assess the impact of anesthetic temperature on the onset and duration of epidural analgesia and various maternal and neonatal health outcomes. The findings may provide evidence on whether warming local anesthetics can reduce the risk of ERMF and improve maternal and neonatal health during labor.