Background A wealth of evidence has indicated that labor epidural analgesia is associated with an increased risk of hyperthermia and overt clinical fever.Recently,evidence is emerging that the epidural analgesia-induced fever is associated with the types of the epidural analgesia and the variations in the epidural analgesia will affect the incidence of fever.The aim of the present study was to investigate the effects of epidural analgesia with 0.075％ or 0.1％ropivacaine on the matal temperature during labor.Methods Two hundred healthy term nulliparas were randomly assigned to receive epidural analgesia with either 0.1％ ropivacaine or 0.075％ ropivacaine.Epidural analgesia was initiated with 10 ml increment of the randomized solution and 0.5 μg/ml sufentanyl after a negative test dose of 5 ml of 1.5％ lidocaine,and maintained with 7 ml bolus doses of the abovementioned mixed analgesics every 30 minutes by the patient-controlled epidural analgesia.The measurements included the matal oral temperature,visual analog scale pain scores,labor events and neonatal outcomes.Results Epidural analgesia with 0.075％ ropivacaine could significantly lower the mean matal temperature at 4 hours after the initiation of analgesia and the oxytocin administration during labor compared with the one with 0.1％ropivacaine.Moreover,0.075％ ropivacaine treatment could provide satisfactory pain relief during labor and had no significant adverse effects on the labor events and neonatal outcomes.Conclusion Epidural analgesia with 0.075％ ropivacaine may be a good choice for the epidural analgesia during labor.