Objective To investigate the causes of labor fever after epidural labor analgesia from the changes of maternal serum interleukin (IL)‑6 and heat shock protein 70 (HSP70) expression. Methods A total of 60 singleton primigravid women with cephalic position who were delivered vaginally after epidural labor analgesia were selected. According to whether their body temperature was ≥37.6 °C during the first stage of labor after epidural labor analgesia, they were divided into two groups: a fever group (n=28) and a normal body temperature control group (n=32). Both groups were compared for general data such as age, weight, height, body mass index, and gestational age. Their Visual Analog Scale (VAS) scores before epidural labor analgesia (T1), after 2 h of epidural labor analgesia, and at the time of opening of the uterine orifice (T2), as well as the duration of epidural labor analgesia, the duration of the period from water breaking to delivery, and the duration of the first stage of labor, the second stage of labor and the third stage of labor were recorded. Furthermore, delivery outcome indicators such as the number of endocervical examinations, the rate of amniotic fluid contamination, the rate of antibiotic use, blood loss during labor, the rate of perineal lateral incision and the rate of forcep use were recorded. Newborn birth weight, Apgar scores at 1, 5 min and 10 min after birth and umbilical artery blood pH value, arterial blood partial pressure of oxygen (PaO2) and arterial blood partial pressure of carbon dioxide (PaCO2) were recorded. The levels of maternal serum IL‑6 and HSP70 at T1, T2 and postoperative 24 h (T3) were measured by enzyme‑linked immunosorbent assay (ELISA). Results There was no difference between the two groups in terms of general information such as age, weight, height, body mass index and gestational age, as well as VAS scores at T1, after 2 h of epidural labor analgesia, and T2, and the duration of the period from water breaking to delivery, the duration of the first stage of labor, the second stage of labor, and the third stage of labor (P>0.05). Both groups showed decreases in VAS scores at 2 h of epidural labor analgesia and at T2, compared with those at T1 (both P<0.05). The fever group presented increases in the duration of maternal epidural labor analgesia, the rate of amniotic fluid contamination, the rate of antibiotic use, and the rate of perineal lateral incision, compared with the control group (P<0.05). No statistical differences were found as to the number of endocervical examinations, blood loss during labor, the rate of forcep use, newborn birth weight, Apgar scores at 1, 5 min and 10 min after birth and the pH value of umbilical artery blood, PaO2, and PaCO2 between the two groups (P>0.05 for all of them). At T2, the fever group showed higher levels of serum IL‑6 than the control group (P<0.05), and the levels of serum IL‑6 in both groups were higher than those at T1 and T3 (both P<0.05). At T2, the levels of maternal serum HSP70 in the control group were higher than those at T1 and T3 (both P<0.05), and the levels of maternal serum HSP70 in the fever group were higher than those at T3 (P<0.05). Conclusions Infection is not the main cause of labor fever after epidural labor analgesia, and aseptic inflammatory response induced by multiple factors may be the main mechanism.