Sixteen million babies were born in 2010, approximately half were by cesarean. Labor
analgesia should be the first choice for these parturients based on the consideration of
security and humanization. However this labor analgesia rate is quite low in China (<5%)
while in western country, this rate is up to 60%. Programmed intermittent epidural bolus
(PIEB) is the latest technique for labor analgesia which has less neurotoxicity theoretically
compared with Continuous Epidural Infusion(CEI) with Patient controlled epidural analgesia
(PCEA) which is used most commonly. In that study, they reported less total local anesthetic
consumption, fewer manual bolus doses and greater patient satisfaction with the PIEB
technique. In China, multiple factors contribute to the reasons of low labor analgesia rate.
From the patient's point of view, worrying about unsatisfied analgesia, and not adapted to
the symptoms of motor block, such as inability to move their legs distressing, both are
important reasons of refusing labor analgesia and preferring to cesarean delivery. Therefore,
in this clinical trial, we plan to find a safer and more effective regimen for labor
analgesia in Chineseparturients. This clinical trial is designed to prove PIEB used
Ropivacaine is safer and more effective than CEI for labor analgesia in Chinese parturients.