Background and Objectives Epidural infusion of 0.2% ropivacaine is recommended by the manufacturer for labor analgesia, but lower concentrations may be effective. The objective of this study was to compare 0.1% ropivacaine with 0.2% ropivacaine and to examine the effect of addition of fentanyl.

Methods In a randomized double-blind study, 58 nulliparous laboring parturients had epidural analgesia established with 0.2% ropivacaine and were then randomized to receive one of the following epidural infusions at 10 mL/h: 0.2% ropivacaine (group R2, n = 19), 0.1% ropivacaine (group R1, n = 19), or 0.1% ropivacaine with 2 μg/mL fentanyl (group RF, n = 20). Supplementary analgesia was provided on request with 5-mL boluses of 0.2% ropivacaine.

Results All solutions provided effective analgesia during early labor, with all groups requiring similar numbers of supplementary top-ups. Visual analog pain scores in groups R2 and RF were equivalent and lower than in group R1 (P = .006). Hypotension was more frequent in group RF compared with groups R2 and R1 (P = .014). Patient and midwife satisfaction and obstetric and neonatal outcomes were similar among groups. Maternal venous plasma concentrations of ropivacaine were greater in group R2 compared with groups R1 and RF (P = .008), but umbilical venous concentrations were similar.

Conclusions We conclude that epidural infusion of 0.1% ropivacaine alone at 10 mL/h provided adequate analgesia in the first stage of labor, and that the addition of 2 μg/mL fentanyl to that concentration improved analgesia to a quality similar to 0.2% ropivacaine alone.