The effect of epidural analgesia with hydromorphone combined with ropivacaine on intrapartum fever in women undergoing vaginal delivery

Epidural-related maternal fever (ERMF) is a well-recognised complication of epidural labor analgesia, with a significantly higher incidence compared to parturients who do not receive epidural analgesia. We hypothesised that hydromorphone combined with ropivacaine during epidural labor analgesia would reduce the incidence of intrapartum fever (body temperature ≥ 38.0 °C) in parturients. This trial was conducted to evaluate the effect of epidural analgesia with hydromorphone combined with ropivacaine on intrapartum fever. All enrolled patients were randomly assigned to receive ropivacaine (Group R) or ropivacaine plus hydromorphone (Group H). Patients in group R received the analgesic pump solutions of 0.1% ropivacaine. Patients in group H received the analgesic pump solutions of 0.1% ropivacaine + hydromorphone 15 µg/mL. The background infusion rate was 8 mL/h, with a PCA bolus of 10 mL and a lockout interval of 30 min. The primary outcome was the incidence of maternal fever after labor analgesia. Fever was defined as a body temperature ≥ 38.0 °C after receiving labor analgesia and TNF-α were recorded before analgesia and postpartum. Six hundred seventeen patients were included in this study. A total of 49 patients in both groups developed intrapartum fever after labor analgesia. The incidence in the Ropivacaine analgesia group was 11.7% (36/308, 95% confidence interval [CI], 8.1–15.3%), while in the Ropivacaine combined with Hydromorphone analgesia group it was 4.2% (13/309, 95% CI, 2.0–6.5%). There was a statistically significant difference in the incidence of fever between the two groups (χ²=11.8, p =0.001; OR=3.0, 95% CI, 1.5–5.8). The body temperature in group R (36.65±0.43 ℃) was significantly higher than that in group H (36.57±0.35 ℃) at T2 ( p =0.012). There was no statistically significant difference in body temperature between the two groups at other time point ( p >0.05). The levels of IL-6 in group R were significantly higher than in group H (38.3±12.2 μg/L and 30.4±8.8 μg/L) postpartum ( p < 0.001). The levels of TNF-α in group R were significantly higher than in group H (67.5±4.9 μg/L and 55.4±4.3 μg/L) postpartum ( p <0.001). There was no statistically significant difference in the incidence of nausea, vomiting, dizziness, shivering, pruritus, drowsiness and hypotension ( p >0.05). Epidural analgesia with hydromorphone combined with ropivacaine in women undergoing vaginal delivery not only could effectively reduce the incidence of ERMF, but also could reduce the rise in body temperature by inhibiting the release of IL-6 and TNF-α after labor analgesia. This trial was registered at http//www.chictr.org.cn(28/06/2024, ChiCTR2400086325).