Impact of Epidural-Related Maternal Fever on Neonatal Outcomes: A Single-Center Retrospective Case-Control Study...

Maternal fever during labor analgesia may arise from infectious causes (such as chorioamnionitis) or noninfectious causes (such as epidural-related maternal fever [ERMF]). While chorioamnionitis is associated with neonatal outcomes, the impact of isolated ERMF remains controversial. This is due, in part, to the potential for occult intrauterine infection, which may not be clinically apparent during labor. Consequently, inadequate consideration of histological chorioamnionitis has limited the scope and validity of previous studies. This study aimed to evaluate the effects of ERMF on neonatal outcomes by excluding confirmed histological chorioamnionitis and minimizing suspected infection using predefined clinical criteria.

This retrospective study included women with singleton term deliveries under labor analgesia between January 2017 and July 2023. Cases with fetal anomalies or growth restriction were excluded. Placental pathological examination was performed when any of the predefined risk-based criteria were met, irrespective of maternal fever: clinical suspicion of chorioamnionitis, prolonged rupture of membranes, and neonatal asphyxia. Among febrile cases, short-term neonatal outcomes were first compared between those with and without histological chorioamnionitis. Subsequently, outcomes were compared between mothers with intrapartum fever (≥38 °C) and those without fever using propensity score matching. Long-term infant development was assessed using a Maternal and Child Health Handbook-based questionnaire.

Overall, 186 matched pairs were included. All matched covariate standardized mean differences were <0.1, confirming acceptable balance. Compared with the nonfever group, the fever group had longer mean ± standard deviation durations from rupture of membranes to delivery (12.9 ± 9.4 vs 8.7 ± 10.9 hours; difference 4.2 hours; 95% confidence interval [CI], 2.17-6.33), first stage of labor (13.2 ± 6.7 vs 9.6 ± 6.3 hours; difference 3.6 hours; 95% CI, 2.32-4.99), and duration of labor analgesia (14.9 ± 9.6 vs 8.6 ± 6.7 hours; difference 6.3 hours; 95% CI, 4.62-8.01), along with a higher incidence of fetal tachycardia (36.0 vs 10.7%; absolute risk difference 25.3%; 95% CI, 12.3-37.2). In contrast, maternal fever was not associated with adverse neonatal outcomes, including umbilical artery pH <7.2, Apgar score <7 at 1 and 5 minutes, or neonatal intensive care unit admission. Growth and developmental milestones assessed at long-term follow-up using the Maternal and Child Health Handbook questionnaire were within the normal range in both groups.

Following exclusion of histological chorioamnionitis, ERMF was associated with prolonged labor and fetal tachycardia but was not associated with adverse short-term neonatal outcomes or impaired long-term development.