Single epidural bolus hydromorphone for acute postpartum pain after vaginal delivery: a randomized clinical trial

Postpartum pain significantly affects maternal recovery and overall health, underscoring the need for effective analgesic strategies. In this randomized controlled trial, 460 term parturients who underwent vaginal delivery were assigned to receive either a single epidural bolus of hydromorphone (HY group, n = 230) or an equivalent volume of normal saline (NS group, n = 230). Within 48 h postpartum, pain scores were significantly lower in the HY group than in the NS group (p < 0.001), with a greater proportion of women achieving pain scores ≤ 3 (76.47% vs. 27.93%; OR = 8.39, 97.5% CI 5.15-13.67). The HY group required fewer supplemental analgesics (6.79% vs. 24.77%; OR = 0.22, 97.5% CI 0.11-0.44), and the time to first rescue analgesia was prolonged (15.63 ± 5.98 vs. 12.01 ± 5.01 h). Although the incidence of adverse effects, including nausea, vomiting, dizziness, pruritus, and urinary retention, was greater in the HY group (p < 0.05), sleep disturbances were less common (5.43% vs. 30.18%; RR = 0.13). Furthermore, the HY Group exhibited superior maternal satisfaction (p < 0.001) and enhanced post-partum autonomy (p = 0.009), whereas no between-group differences in inflammatory markers were observed. Low-dose epidural hydromorphone provides effective postpartum pain management and represents a viable approach for acute postpartum analgesia, contingent on a favorable risk-benefit profile.Trial registration number: ChiCTR2200064687 (registration date: October 14, 2022; https://www.chictr.org.cn/ ).