title: A review of prospectively controlled comparisons of epidural with non-epidural forms of pain relief during labour.
abstract: OBJECTIVE
  To assess the extent to which hypotheses about potential adverse effects of epidural analgesia during labour can be tested using evidence from controlled comparisons of epidural with non-epidural forms of pain relief.
  
  
  METHODS
  Prospective studies in which an attempt had been made to use random allocation to generate comparable groups of women receiving epidural and non-epidural forms of pain relief during labour. IDENTIFICATION OF RELEVANT STUDIES: Systematic hand search of a total of 36 anaesthetic, obstetric and general journals, and more than 30 other journals (1950-1990), and a search of MEDLINE (1966-1990).
  
  
  METHODS
  Data were abstracted from published reports of 9 controlled trials, involving a total of 600 women. It was possible to obtain some missing information and data from the investigators.
  
  
  RESULTS
  Very few postulated effects of epidural block during labour can be confirmed or rejected on the basis of the evidence generated by the small number of controlled trials. Evidence derived from these trials confirms that epidural block provides more effective relief of pain than alternatives; and that if it is continued during the second stage of labour, it can cause a substantial increase in the use of instrumental delivery.
  
  
  CONCLUSIONS
  Considering the very widespread use of epidural block during labour, remarkably little is known about its short-term and long-term effects. In view of hypotheses about potentially important adverse effects, there is still a need to conduct larger, better designed randomised controlled trials.
authors.affiliation: Department of Anaesthetics, City General Hospital, Stoke-on-Trent ST4 6QG, UK.
authors.forename: C J
authors.initials: CJ
authors.lastname: Howell
authors.forename: I
authors.initials: I
authors.lastname: Chalmers