Editor—In their systematic review Liu et al show that epidural analgesia does not increase the caesarean section rate, which is welcome.1 Unlike previous meta-analyses, this one included only studies of nulliparous women receiving low concentration epidural infusions, in order to re-examine their effect on instrumental vaginal delivery, in the belief that low concentration infusions of local anaesthetic are associated with fewer abnormal deliveries than higher concentrations.
Figure 1.
Credit: BSP LAURENT/SPL
They cite the COMET trial, which could compare only low and high dose bolus administration.2 There have been at least five other randomised comparisons of low and high dose boluses, three showing no significant difference in delivery outcome, but aggregation of all the data shows a significant effect.3 By contrast none out of six comparisons of low (usually 0.0625% bupivacaine) and high concentration infusions showed a difference in delivery type, despite randomising over 800 women.3 Had any randomised trials compared low dose bolus epidurals with systemic opioid analgesia, they might have found no significant effect on instrumental vaginal delivery.
The authors say that neonatal outcomes may be better with epidural analgesia. Since 1974 many studies showed improved neonatal status and protection from the adverse effects of a pronged second stage of labour with epidural analgesia, and meta-analysis has shown a significant benefit to the newborn in Apgar score and acid base status with epidural analgesia of all types, compared with systemic opioids.4
Such good news is disregarded by many groups, who still consider epidural analgesia an undesirable interference.5 Let us hope that this latest evidence will receive better attention.
Competing interests: None declared.
References
- 1.Liu EHC, Sia ATH. Rates of caesarean section and instrumental vaginal delivery in nulliparous women after low concentration epidural infusions or opioid analgesia: systematic review. BMJ 2004;328: 1410-2. (12 June.) [DOI] [PMC free article] [PubMed] [Google Scholar]
- 2.COMET study group. Effect of low-dose mobile versus traditional epidural techniques on mode of delivery: a randomised controlled trial. Lancet 2001;358: 19-23. [DOI] [PubMed] [Google Scholar]
- 3.Reynolds F, Russell R, Porter J, Smeeton N. Does the use of low dose bupivacaine infusion increase the normal delivery rate? Int J Obstet Anesthesia 2003;12: 156-63. [DOI] [PubMed] [Google Scholar]
- 4.Reynolds F, Sharma S, Seed PT. Analgesia in labour and funic acid-base balance: a meta-analysis comparing epidural with systemic opioid analgesia. Br J Obstet Gynaecol 2002;109: 1344-53. [PubMed] [Google Scholar]
- 5.Moss L. Midwives want investigation into birthing procedures. 20 May 2004. http://news.scotsman.com/latestcfm?id=2954577 (accessed 15 July 2004).