Subcutaneous versus intravenous fentanyl for labor pain management: A multicenter randomized controlled trial.

BACKGROUND: Labor pain is the most intense pain experienced in woman's life. Epidural anesthesia is recommended as the most effective method for pain relief, but it has several limitations. Fentanyl is a high analgesic potency with short-acting duration, but the large-scale trials assessing the effectiveness and safety in labor pain management are still limited.

OBJECTIVES: To compare the effectiveness and harm as well as maternal satisfaction of subcutaneous (S.C.) versus intravenous (I.V.) fentanyl for labor pain management.

STUDY DESIGN: We conducted a multicenter open label randomized controlled trial. A total of 226 women were randomized to receive I.V. or S.C. fentanyl for labor pain management. Pain scores were evaluated before and after fentanyl administration at 5, 30, 60 minutes and then every 60 minutes until delivery. The data was analyzed based on intention-to-treat (ITT) principle.

RESULTS: Both I.V. and S.C. fentanyl significantly decreased labor pain from baseline to delivery, overall mean change -1.39 (95% confidence interval [CI], -1.62 to -1.17), and -0.89 (95% CI -1.24 to -0.05), respectively. The reduction of pain score between the two groups was not different, overall mean difference -0.35 (95% CI -0.76 to 0.05). Maternal satisfaction was high for both I.V. and S.C. fentanyl, 89.4% and 93.8%, respectively. There was no difference of maternal satisfaction rate between the two groups, relative risk 0.95 (95%CI 0.88 to 1.03). No serious maternal and neonatal adverse effects were observed.

CONCLUSION: Both I.V. and S.C. fentanyl were safe and significantly reduced pain from baseline to delivery among low-risk pregnancies. Maternal satisfaction in childbirth experience was high regardless of the route of administration of fentanyl administration. No serious adverse effects of fentanyl were observed in both mothers and neonates.