title: Types of intra-muscular opioids for maternal pain relief in labour.
abstract: BACKGROUND
  Pethidine is the most widely used intra-muscular opioid for the relief of labour pain. However concerns have been raised about its effectiveness and the possibility of depressing respiration in newborns.
  
  
  OBJECTIVE
  The objective of this review was to assess the effects of different opioids (and different doses of the same opioid) administered intra-muscularly in labour.
  
  
  METHODS
  We searched the Cochrane Pregnancy and Childbirth Group trials register, the Cochrane Controlled Trials Register (Cochrane Library, issue 4, 1997) and reference lists of articles.
  
  
  METHODS
  Randomised trials comparing the effects of different currently used opioids (and different doses of the same opioid) administered intramuscularly in labour for women who request systemic analgesia.
  
  
  METHODS
  Two reviewers assessed trial quality and extracted data. Analysis was based on the groups as randomly allocated.
  
  
  RESULTS
  Sixteen trials were included. There were problems with methodological quality of some of the trials, and lack of consistency in the way various outcomes were reported. There was no evidence of a difference between pethidine and tramadol in terms of pain relief, interval to delivery, or instrumental or operative delivery. There appeared to be more adverse effects such as nausea and vomiting and drowsiness with pethidine. Maternal pain relief seemed almost identical between the meptazinol and pethidine groups, whether assessed as maternal satisfaction with pain relief, visual analogue scales, or use of other pain relief, but meptazinol gave rise to slightly more side effects. Maternal satisfaction with pain relief appeared similar for pentazocine and pethidine, with more frequent nausea and vomiting with pethidine.
  
  
  CONCLUSIONS
  There is not enough evidence to evaluate the comparative efficacy and safety of the various opioids used for analgesia in labour.
authors.affiliation: Medical Statistics Unit, London School of Hygiene and Tropical Medicine, Room 121, Keppel Street, London, UK, WC1E 7HT. d.elbourne@lshtm.ac.uk
authors.forename: D
authors.initials: D
authors.lastname: Elbourne
authors.forename: R A
authors.initials: RA
authors.lastname: Wiseman
mesh_terms: D016362:Analgesia, Obstetrical; D000701:Analgesics, Opioid / Q000008:administration & dosage / Q000009:adverse effects; D005260:Female; D006801:Humans; D007273:Injections, Intramuscular; D007743:Labor, Obstetric; D008614:Meperidine / Q000008:administration & dosage / Q000009:adverse effects; D010146:Pain / Q000188:drug therapy*; D011247:Pregnancy
chemical_list: D000701:Analgesics, Opioid; D008614:Meperidine