Epidural hydromorphone–ropivacaine for post-episiotomy analgesia in primiparous women: a randomized controlled trial

Abstract Background Post-episiotomy pain is a common postpartum discomfort among primiparous women. Epidural analgesia using the local anesthetic ropivacaine alone has limitations such as insufficient duration of postoperative analgesia and poor pain control in the mid-to-late postoperative period. This study aims to explore a more optimal postoperative analgesic regimen by evaluating the clinical efficacy and safety of ropivacaine with hydromorphone for post-episiotomy analgesia in primiparous women, with a focus on the duration of analgesia, pain control efficacy, recovery-related indicators, and the incidence of adverse events. Methods A randomized controlled trial was conducted involving 80 primiparous patients who received neuraxial labor analgesia and underwent episiotomy between April 2025 and September 2025. Patients were randomly allocated to either Group R (ropivacaine alone) or Group RH (ropivacaine with hydromorphone), with 40 patients in each group. Following delivery and umbilical cord clamping, Group R received epidural ropivacaine (20 mg) diluted in 6 mL of 0.9% sodium chloride, while Group RH received a combination of ropivacaine (20 mg), hydromorphone (0.4 mg), and 6 mL of 0.9% sodium chloride. The primary outcome was analgesic efficacy, specifically including the time to first pain onset after surgery and the Visual Analog Scale (VAS) scores at 6, 12, and 24 h postoperatively; the secondary outcomes were postoperative recovery parameters (time to first flatus and time to first ambulation) and the incidence of adverse events. Results Compared with Group R, the time to first onset of pain in Group RH was significantly prolonged, and the Visual Analog Scale (VAS) scores at 6, 12, and 24 h postoperatively were all lower than those in Group R ( p < 0.05), remaining at a low level. In addition, the total duration of first ambulation in parturients was longer than that in Group R, and the incidence of postoperative nausea was lower than that in Group R (all p < 0.05). There were no statistically significant differences in the time to first flatus, vomiting and motor block between the two groups ( p > 0.05). Conclusions Epidural administration of ropivacaine with hydromorphone following episiotomy significantly enhanced analgesic efficacy and duration, facilitated postoperative recovery, and reduced the incidence of adverse events in primiparous women. These findings support the clinical utility of hydromorphone as an adjunct to ropivacaine for post-episiotomy analgesia. Trial registration This trial was registered at https://www.medicalresearch.org.cn/ (ChiCTR2500101509) on April 25, 2025.