Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2025 Feb 22;25(1):96.
doi: 10.1186/s12871-025-02972-9.

Predictive value of the neutrophil-to-lymphocyte ratio for epidural labor analgesia-associated intrapartum fever: a retrospective single-center study

Lei Li  1 , Xiao-Tong Yang  1 , Jiang Zou  1 , Jian Zhang  1 , Xiao-Hai Xie  1 , Jing-Hui Liu  1 , Ben-Zhen Chen  2
Affiliations

Predictive value of the neutrophil-to-lymphocyte ratio for epidural labor analgesia-associated intrapartum fever: a retrospective single-center study

Lei Li et al. BMC Anesthesiol. .

Abstract

Background: Studies have indicated that epidural analgesia increases the risk of maternal fever during labor, possibly due to non-infectious inflammation. The neutrophil-to-lymphocyte ratio (NLR) is a crucial indicator of inflammation, with a higher NLR potentially signaling worse patient adverse outcomes. The present study explores whether NLR has clinical predictive value for epidural analgesia-related maternal fever (ERMF).

Methods: A retrospective analysis was performed for 1602 women who voluntarily requested analgesia for epidural labor from January 2023 to June 2024. Univariate and multivariate logistic regression analyses were applied to identify the factors influencing intrapartum fever, and the association between NLR and ERMF was explored. The receiver operating characteristic (ROC) curve was used to assess the area under the curve (AUC) of NLR for intrapartum fever, and the nearest ascending index was utilized to determine the cut-off value.

Results: A total of 1602 parturients were included, of which 160 (10%) had intrapartum fever. Body mass index (BMI) (OR = 1.132, 95% CI: 1.027-1.246, P = 0.012), the duration of the first stage of labor (OR = 1.002, 95% CI: 1.001-1.003, P < 0.001), percentage of lymphocytes (OR = 1.205, 95%CI: 1.073-1.354, P = 0.012) and NLR (OR = 1.964, 95% CI: 1.462-2.639, P < 0.001) were independent risk factors for intrapartum fever. High NLR levels were associated with a higher incidence of ERMF at subgroups of ages < 35 years (OR = 1.343, 95%CI: 1.215-1.486, P < 0.001), ages ≥ 35 years (OR = 1.274, 95%CI: 1.105-1.468, P = 0.01), BMI < 24 kg/m2 (OR = 1.326, 95% CI: 1.176-1.495, P < 0.001), BMI ≥ 24 kg/m2 (OR = 1.515, 95%CI: 1.147-2.000, P = 0.003), first stage of labor < 600 min (OR = 1.466, 95%CI: 1.241-1.733, P < 0.001), and first stage of labor ≥ 600 min (OR = 1.257, 95%CI: 1.109-1.424, P < 0.001). Maternal NLR levels greater than 6.305 (AUC = 0.702, 95%CI: 0.634-0.768, P < 0.001) were good predicators of intrapartum fever.

Conclusions: High NLR is associated with EMRF, and NLR is a viable predictor of early identification of the occurrence of EMRF, which may be beneficial for pregnancy outcomes.

Keywords: Epidural analgesia; Labor; Maternal fever; Neutrophil-to-lymphocyte ratio.

PubMed Disclaimer

Conflict of interest statement

Declarations. Ethics approval and consent to participate: The study was approved by the Ethics Committee of Sichuan Women and Children’s Hospital (20240723-320). The need for informed consent was waived by the Sichuan Provincial Women and Children’s Hospital Review Board because no protected health information was used in this retrospective study. Consent for publication: Not applicable. Competing interests: The authors declare no competing interests.

Figures

Fig. 1
Fig. 1
Participant flow chart
Fig. 2
Fig. 2
ROC curve analysis for maternal NLR for predicting ERMF before epidural analgesia
Fig. 3
Fig. 3
Association between NLR levels and the incidence of ERMF in subgroups of age, BMI, and duration of the first stage of labor
See this image and copyright information in PMC

References

    1. Morton S, Kua J, Mullington CJ. Epidural analgesia, intrapartum hyperthermia, and neonatal brain injury: a systematic review and meta-analysis. Br J Anaesth. 2021;126:500–15. - PubMed
    1. Patel S, Ciechanowicz S, Blumenfeld YJ, Sultan P. Epidural-related maternal fever: incidence, pathophysiology, outcomes, and management. Am J Obstet Gynecol 2023, 228:S1283-S1304.e1. - PubMed
    1. Shuai F, Jia J, Lin P. Effects of using epidural analgesia during delivery on maternal and infant outcomes. Gynecol Obstet Invest. 2022;87:46–53. - PubMed
    1. Hensel D, Zhang F, Carter EB, Frolova AI, Odibo AO, Kelly JC, Cahill AG, Raghuraman N. Severity of intrapartum fever and neonatal outcomes. Am J Obstet Gynecol. 2022;227:e5131–513.e8. - PubMed
    1. Eltzschig HK, Lieberman ES, Camann WR. Regional anesthesia and analgesia for labor and delivery. N Engl J Med. 2003;348:319–32. - PubMed

LinkOut - more resources