title: Rates of caesarean section and instrumental vaginal delivery in nulliparous women after low concentration epidural infusions or opioid analgesia: systematic review.
abstract: OBJECTIVE
  To compare the effects of low concentration epidural infusions of bupivacaine with parenteral opioid analgesia on rates of caesarean section and instrumental vaginal delivery in nulliparous women.
  
  
  METHODS
  Medline, Embase, the Cochrane controlled trials register, and handsearching of the International Journal of Obstetric Anesthesia.
  
  
  METHODS
  Randomised controlled trials comparing low concentration epidural infusions with parenteral opioids.
  
  
  RESULTS
  Seven trials fulfilled the inclusion criteria for meta-analysis. Epidural analgesia does not seem to be associated with an increased risk of caesarean section (odds ratio 1.03, 95% confidence interval 0.71 to 1.48) but may be associated with an increased risk of instrumental vaginal delivery (2.11, 0.95 to 4.65). Epidural analgesia was associated with a longer second stage of labour (weighted mean difference 15.2 minutes, 2.1 to 28.2 minutes). More women randomised to receive epidural analgesia had adequate pain relief, with fewer changing to parenteral opioids than vice versa (odds ratio 0.1, 0.05 to 0.22).
  
  
  CONCLUSIONS
  Epidural analgesia using low concentration infusions of bupivacaine is unlikely to increase the risk of caesarean section but may increase the risk of instrumental vaginal delivery. Although women receiving epidural analgesia had a longer second stage of labour, they had better pain relief.
authors.affiliation: Department of Anaesthesia, National University Hospital, 5 Lower Kent Ridge Road, Singapore 119074. analiue@nus.edu.sg
authors.forename: E H C
authors.initials: EH
authors.lastname: Liu
authors.forename: A T H
authors.initials: AT
authors.lastname: Sia
mesh_terms: D015360:Analgesia, Epidural; D016362:Analgesia, Obstetrical; D000701:Analgesics, Opioid / Q000008:administration & dosage*; D000779:Anesthetics, Local / Q000008:administration & dosage*; D002045:Bupivacaine / Q000008:administration & dosage*; D002585:Cesarean Section / Q000706:statistics & numerical data*; D036861:Delivery, Obstetric / Q000295:instrumentation*; D005260:Female; D006801:Humans; D007744:Obstetric Labor Complications / Q000628:therapy*; D010298:Parity; D011247:Pregnancy; D016032:Randomized Controlled Trials as Topic; D012307:Risk Factors; D014620:Vacuum Extraction, Obstetrical
chemical_list: D000701:Analgesics, Opioid; D000779:Anesthetics, Local; D002045:Bupivacaine