Role of mitochondrial DNA level in epidural-related maternal fever: a single-centre, observational, pilot study

INTRODUCTION

Epidural analgesia has been associated with intrapartum maternal fever development. Epidural-related maternal fever (ERMF) is believed to be based on a non-infectious inflammatory reaction. Circulating cell-free mitochondrial deoxyribonucleic acid (mtDNA) is one of the possible triggers of sterile inflammatory processes; however, a connection has not been investigated so far. Therefore, this study aimed to investigate cell-free mtDNA alterations in women in labour with ERMF in comparison with non-febrile women.

MATERIAL AND METHODS

A total of 60 women in labour were assessed for maternal temperature every 4 h and blood samples were obtained at the beginning and after delivery. Depending on the analgesia and the development of fever (axillary temperature ≥ 37.5 °C), the women were allocated either to the group of no epidural analgesia (n = 17), to epidural analgesia no fever (n = 34) or to ERMF (n = 9). Circulating cell-free mtDNA was analysed in the maternal plasma for the primary outcome whereas secondary outcomes include the evaluation of inflammatory cytokine release, as well as placental inflammatory signs.

RESULTS

Of the women with epidural analgesia, 20% (n = 9) developed ERMF and demonstrated a decrease of circulating mtDNA levels during labour (p = 0.04), but a trend towards higher free nuclear DNA. Furthermore, women with maternal pyrexia showed a 1.5 fold increased level of Interleukin-6 during labour. A correlation was found between premature rupture of membranes and ERMF.

CONCLUSIONS

The pilot trial revealed an evident obstetric anaesthesia phenomenon of maternal fever due to epidural analgesia in 20% of women in labour, demonstrating counterregulated free mtDNA and nDNA. Further work is urgently required to understand the connections between the ERMF occurrence and circulating cell-free mtDNA as a potential source of sterile inflammation.

TRIAL REGISTRATION

NCT0405223 on clinicaltrials.gov (registered on 25/07/2019).

Factors associated with epidural-related maternal fever in low-risk term women: a systematic review

BACKGROUND

The underlying mechanism of epidural-related maternal fever (ERMF) is not fully understood. This systematic review aimed to identify factors associated with ERMF in low-risk, full-term women using neuraxial analgesia.

METHODS

PubMed, Embase, Web of Science, CENTRAL, and Wanfang Data were searched from inception to September 10, 2022 with no language restriction. Studies reported descriptive data regarding the factors associated with ERMF. A random effects model meta-analysis was used to pool the raw data of univariate analyses for each identified factor. Sensitivity and subgroup analyses were performed to explore possible sources of heterogeneity.

RESULTS

Eighteen observational studies involving 33 427 women were included, with 18 factors eligible for meta-analyses. Higher body mass index, baseline temperature, admission maternal interleukin-6 levels and white blood cell counts, nulliparity, increasing gestational age, longer duration of labor and rupture of membranes, increasing number of vaginal examinations, oxytocin use, higher birth weight, lower cervical dilation at initiation of analgesia, and longer analgesia duration were associated with increased risk of ERMF, while intermittent compared with continuous epidural dosing was associated with a decreased risk of ERMF (odds ratio 0.25, 95% CI 0.16 to 0.48, P < 0.001). However, heterogeneity among studies was high and the quality of evidence was low for these meta-analyses, except for intermittent epidural dosing.

CONCLUSIONS

Many factors are associated with ERMF but may not be independent or causal. Further study is needed to clarify the interactions of these factors in ERMF development and whether modification of these factors might influence risk of ERMF.

[Effect of transcutaneous electrical acupoint stimulation on epidural-related maternal fever in parturients undergoing epidural labor analgesia]

OBJECTIVE

To evaluate the therapeutic effect and safety of transcutaneous electrical acupoint stimulation (TEAS) on epidural-related maternal fever in parturients undergoing epidural labor analgesia.

METHODS

A total of 198 primiparas with single birth, full-term pregnancy and head position were recruited and randomized into a TEAS group (98 cases) and a control group (100 cases). In the TEAS group, after epidural labor analgesia, TEAS was applied to bilateral Hegu (LI4) and Quchi (LI11), once an hour, for 30 min each time, till the end of childbirth. In the control group, after epidural labor analgesia, TEAS electrodes were attached to the same acupoints, but without electric stimulation. Maternal tympanic temperature and the score of Visual Analogue Score (VAS) were measured before analgesia, at 1, 2, 3, 4 and 5 h after analgesia and during labor respectively and maternal fever rate was evaluated in the parturients of two groups. Separately, before analgesia, 2 h after analgesia and during labor, the levels of serum interleukin (IL-6) and IL-1β were determined in the parturients of two groups. The duration of labor, the mode of labor, oxytocin dosage, postpartum hemorrhage, neonatal Apgar scores, time of labor analgesia, labor analgesic consumption and adverse effects were recorded in the parturients of two groups.

RESULTS

Maternal tympanic temperature increased progressively in two groups as analgesic time prolonged. Tympanic temperature at 3, 4 and 5 h after analgesia and du-ring labor, and maternal fever rate during labor in the TEAS group were all lower than those in the control group respectively (P<0.05). The levels of serum IL-6 and IL-1β increased after analgesia in the parturients of two groups. The serum IL-6 level during labor and the level of IL-1β at 2 h after analgesia and during labor in the parturients of the TEAS group were lower than those in the control group (P<0.05). The analgesic consumption in the TEAS group was less than that in the control group (P<0.05). The incidence of chills in the TEAS group was lower than that in the control group (P<0.05). The differences were not statistical in VAS score, duration of labor, mode of labor, oxytocin dosage, postpartum hemorrhage, time of labor analgesia and neonatal Apgar score, as well as the incidence of urine retention, nausea and vomiting and urinary retention between two groups (P>0.05).

CONCLUSION

Transcutaneous electrical acupoint stimulation at LI11 and LI4 is conductive to relieving epidural-rela-ted maternal fever and reducing serum levels of IL-6 and IL-1β in the parturients undergoing epidural labor analgesia. It is safe and effective in clinical application.