1Stienstra R,Jonker T,Bourdrez P,et al. Ropivacaine 0. 25% versus bupivacaine 0.25% for continuous epidural analgesia in labor : a double blind comparison . Anesth Analg, 1995,80(2) :285-289.
2Collis RE,Plaat FS, Morgan BM. Comparson of midwife top-ups ,continuous infusion and patient-controlled epidural analgesia for maintaining mobility after a low-dose combined spinal-epidural. Br J Anaesth, 1999,82 (2) :233-236.
3Holger KE,Ellice SL,William RC.Regional anesthesia and analgesia for labor and delivery.N Engl J Med,2003,348:319-332.
4Babara LL,Stephen HH.The effects of epidural analgesia on labor,maternal,and neonatal outcomes: a systematic review.Am J Obstet Gynecol,2002,186:S69-77.
5Alexander JM,Sharma SK,McIntire DD,et al.Epidural analgesia lengthens the Friedman active phase of labor.Obstet Gynecol,2002,100:46-50.
6Zhang J,Troendle JF,Yancey MK.Reassessing the labor curve.Am J Obstet Gynecol,2002,187:824-828.
7Theodore RM,David MK.Labor pain management in united states: Understanding patterns and the issue of choice.Am J Obstet Gynecol,2002,186:S173-180.
