We are gratified by the interest Drs. Tsen and Segal have shown in our study comparing epidural and combined spinal–epidural labor analgesia. 1Unlike in their earlier study, 2we found no shortening of the first stage of labor associated with the combined spinal–epidural technique. In their letter, Drs. Tsen and Segal correctly point out that differences in obstetric and anesthetic management could account for their result. Our study was designed to minimize the differences between these two techniques. Hence, all patients received the same drugs (sufentanil and bupivacaine), all patients received the same dose of sufentanil at induction (10 μg), and all patients had an identical epidural infusion started immediately after induction of analgesia. Under these conditions, the durations of the first and second stages of labor and the methods of delivery were identical among both parous and nulliparous women allocated to receive either anesthetic technique. We found the same results when we included only protocol-compliant patients in our analysis.

While the impact of epidural analgesia on the progress and outcome of labor remains the source of controversy, 3there is no evidence that choosing between epidural or intrathecal injection of small doses of opioids and local anesthetics for induction of analgesia has any clinically significant impact on the overall duration or outcome of labor. 4 

Norris MC, Fogel ST, Conway-Long C: Combined spinal–epidural versus  epidural labor analgesia. A nesthesiology 2001; 95: 913–20
Tsen LC, Thue B, Datta, Segal S: Is combined spinal–epidural analgesia associated with more rapid cervical dilation in nulliparous patients when compared with conventional epidural analgesia? A nesthesiology 1999; 91: 920–5
Halpern SH, Leighton BL, Ohlsson A, Barrett JF, Rice A: Effect of epidural vs parenteral opioid analgesia on the progress of labor: A meta-analysis. JAMA 1998; 280: 2105–10
Bucklin BA, Chestnut DH, Hawkins JL: Intrathecal opioids versus epidural local anesthetics for labor analgesia: A meta-analysis. Reg Anesth Pain Med 2002; 27: 23–30