Nalbuphine as a Bridge to Delayed Epidural Analgesia: A Randomized Trial on First-Stage Labor Duration

Purpose: The present study aimed to investigate whether nalbuphine-assisted delayed epidural analgesia, as compared with early epidural analgesia, exerts an effect on the duration of the first stage of labor in nulliparous women. Patients and Methods: A total of 120 nulliparous women were enrolled in the final statistical analysis between July 2024 and March 2025. Participants were randomly allocated to either the Early Epidural Analgesia group (normal saline control, NS group) or the Delayed Epidural Analgesia group (nalbuphine-assisted, NB group). The primary outcome measure was the duration of the first stage of labor. Results: The Kaplan-Meier survival curve analysis demonstrated that the duration of the first stage of labor was significantly shorter in the nalbuphine group than in the normal saline group (hazard ratio [HR] = 1.629, 95% confidence interval [CI]: 1.082– 2.455, P < 0.05), indicating a statistically significant difference. No between-group statistical differences were observed in the incidence of postpartum hemorrhage, oxytocin administration rate, labor induction methods, episiotomy rate, amniotic fluid contamination, maternal fever, nausea, vomiting, or cesarean section rate. Conclusion: For nulliparous women, nalbuphine-assisted delayed epidural analgesia can shorten the duration of the first stage of labor compared with early epidural analgesia (administered at cervical dilation ≤ 3 cm). Keywords: nalbuphine, epidural anesthesia, labor analgesia, first stage of labor, pregnancy