Randomized Controlled Trial

The influence of continuous epidural bupivacaine analgesia on the second stage of labor and method of delivery in nulliparous women.

Anesthesiology. 1987 Jun 1;66(6):774-80.
Randomized Controlled Trial

Continuous infusion epidural analgesia during labor: a randomized, double-blind comparison of 0.0625% bupivacaine/0.0002% fentanyl versus 0.125% bupivacaine.

Anesthesiology. 1988 May 1;68(5):754-9.
Randomized Controlled Trial

Comparison of 0.25% ropivacaine and bupivacaine for epidural analgesia for labor and vaginal delivery.

J Clin Anesth. 1997 Nov 1;9(7):564-8.