Predictive value of neutrophil-to-lymphocyte ratio on admission for intrapartum maternal fever in parturients undergoing epidural analgesia: A retrospective cohort study using propensity score-matched analysis

Objective: To identify the predictive value of the neutrophil-to-lymphocyte ratio (NLR) on admission for intrapartum maternal fever in parturients undergoing epidural analgesia (EA). Methods: In this retrospective cohort study, propensity score matching (PSM) was applied to address covariates. Univariate and multivariate regression analyses were implemented in sequence to find out the factors influencing intrapartum fever. The receiver operating characteristics curve was applied to determine the area under the curve (AUC) of NLR for intrapartum fever. Results: NLR and duration of EA were independent risk factors for intrapartum fever. The AUC of the combined indicator (NLR + duration of EA) was higher than that of NLR (AUC = 0.583, 95% confidence interval [CI] 0.53-0.64) and duration of EA (AUC = 0.702, 95% CI 0.66-0.75), reaching 0.715 (95% CI 0.67-0.76; p < 0.001). NLR increased predictive performance for intrapartum fever when added to the duration of EA (net reclassification index 0.076, p = 0.022; integrated discrimination improvement 0.020, p = 0.002). Conclusion: NLR has limited predictive power for intrapartum fever. The combination of NLR and duration of epidural analgesia may be considered a promising predictor for intrapartum maternal fever in parturients undergoing epidural analgesia. Synopsis: The neutrophil-to-lymphocyte ratio is an accessible predictor for the early identification of parturients at risk of intrapartum fever.