Background. The relevance of this study is dictated by the widespread use of epidural analgesia (EA) during labor, the adverse effects of which must be taken into account.
Objective. Evaluation of the role of the infectious agent in the development of fever in parturient women who underwent EA according to indications.
Methods. The prospective cohort study included 150 patients whose childbirths occurred in the Maternity Hospital No. 2 of the Inozemtsev City Clinical Hospital (Moscow) in the period from October 1, 2022 to May 4, 2023. The main group consisted of 100 parturient women who were anesthetized by EA for pain syndrome (7 or more points on the visual analogue scale), the comparison group included 50 patients whose childbirths were carried out in the absence of neuraxial anesthesia. 49 patients with EA-assisted childbirth and T<37.5°C were included in subgroup A, 51 patients with T≥37.5°C – subgroup B. In these subgroups, a comparative analysis of the course of childbirth and type of delivery, serum levels of pro-inflammatory cytokine interleukin-6 (IL-6), results of histological and microbiological studies of placentas and cultures for the microflora of vaginal discharge, one-factor correlation analysis to clarify the reliability of the identified relationships were performed.
Results. The analysis revealed a statistically significant association of using of EA with leukocyte infiltration of the placentas, which was detected with this method of analgesia 3 times more often than in its absence: 33 (33%) and 6 (12%) out of 100 patients, respectively ( p=0.004). There were 17 cases of chorioamnionitis (CA) reported in the EA group. According to the further analysis of subgroups, it was noted that leukocyte infiltration of placentas in patients with T≥37.5°C was recorded 2.5 times more often than in women with normothermia: 23 (43%) of 54 and 16 (17%) of 96 patients (p=0.001). Leukocyte infiltration against the background of EA was associated not only with an increase in the body temperature of parturient women, but also with an increase in the most active pro-inflammatory pyrogenic cytokine IL-6 (p=0.005). The frequency of detection of opportunistic microflora in placental tissue in both subgroups was comparable, indicating that there was no reliable relationship between the bacterial nature of CA and epidural anesthesia.
Conclusion. Thus, the obtained relationships confirmed the dominant role of the non-infectious inflammatory process in the pathogenesis of fever against the background of EA. A more detailed understanding of the pathophysiological mechanisms of the condition under study will allow to develop the most effective measures for the prevention and treatment of EA-associated fever, and improve perinatal outcomes.

Keywords: histological examination of placentas, non-infectious inflammatory process, prospective cohort study, epidural analgesia, intrauterine infection, fever