Rates of caesarean section and instrumental vaginal delivery in nulliparous women after low concentration epidural infusions or opioid analgesia: systematic reviewBMJ 2004; 328 doi: https://doi.org/10.1136/bmj.38097.590810.7C (Published 10 June 2004) Cite this as: BMJ 2004;328:1410
All rapid responses
EDITOR-The systematic review by Liu and Sia concludes that low dose
epidurals do not increase the rate of caesarean sections. The results
of this review will reassure the multi-disciplinary labour ward teams of
the relative safety of epidural anaesthesia in providing pain relief to
women in labour.
It is recommended by professional groups that the majority of
caesarean sections should be performed under regional nerve block. This
is because there is less morbidity and mortality associated with it than
with general anaesthesia.
We undertook a 15-month retrospective case note review of hospital
notes at a district general hospital from April 2003 to examine
anaesthesia usage during caesarean sections. There were 3418 deliveries of
which, 748 (21.9%) were caesarean sections. 50 (6.8%) women underwent
general anaesthesia, which is comparable to the figures in the
literature. Of particular interest we found that 21 (42%) of the
general anaesthesia cases were because the epidural, which was in-situ
failed or could not be extended for surgical anaesthesia and there was no
time to site a spinal. This was identified as an area for improvement by
the department. After a multi-disciplinary team meeting it was agreed that
midwives and anaesthetists should regularly check on the effectiveness of
the sited epidural so that if an emergency arose, which necessitated
either instrumentation or caesarean section the regional nerve block could
still cover it. A re-audit of this is now due.
A working in-situ epidural may not continue to deliver pain relief
throughout labour. Our results add to Liu and Sia’s findings by
highlighting the importance of monitoring the block provided by epidurals
once they are sited, especially in women who are suspected by the labour
ward team to require an emergency caesarean section.
1. Liu E, Sia T. Rates of caesarean section and instrumental vaginal
delivery in nulliparous women after low concentration epidural infusions
or opiod analgesia: systematic review. BMJ 2004;328:1410-1412.
2. Thomas J, Paranjothy S. Royal College of Obstetricians and
Gynaecologists Clinical Effectiveness Support Unit. National Sentinel
Caesarean Section Audit Report. RCOG Press, 2001.
3. Morgan B, Aulakh J, Barker J, Reginald P, Goroszeniuk T,
Trojanowski A. Anaesthetic morbidity following caesarean section under
epidural or general anaesthesia. Lancet 1984;323:328-330.
Competing interests: No competing interests
Another systematic review in a prestigious general journal showing
that epidural analgesia does not increase the caesarean section rate is to
Unlike previous meta-analyses,[1-3] Liu and Sia have 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 infusions containing low concentrations of
local anaesthetic are associated with a lower risk of operative delivery
than are higher concentrations.
They cite the COMET trial, which could
not have demonstrated this, as in this trial it was only possible to
compare low and high dose bolus administration. There have been at least
five other randomised comparisons of low and high dose epidural boluses,
two of which showed a significant difference in delivery outcome, but
aggregation of all the data does indeed show a significant effect.
contrast there have also been at least six randomised trials of low and
high concentration infusions, none of which demonstrated a reduction in
normal delivery rates with low concentrations, despite randomising over
I would not describe an infused concentration of bupivacaine of
0.125% with opioid as low; this is overkill: such a concentration is
effective when bupivacaine is infused without opioid. In the infusion
studies referred to above, the usual ‘low’ concentration was 0.0625%, yet
no increase in normal deliveries was achieved. Had Liu and Sia analysed
comparisons of low dose bolus epidurals with systemic opioid analgesia, it
is possible that they might have found no significant effect on
instrumental vaginal delivery.
Liu and Sia state that neonatal outcomes may be better with epidural
analgesia. In 1974 three studies demonstrated improved fetal acid-base
status and protection from the adverse effects of a pronged second stage
with epidural analgesia.[6-8] Since then randomised studies have appeared,
and meta-analysis has shown a significant benefit to the newborn in acid-
base status with epidural analgesia of all types, compared with systemic
Such good news is disregarded by radical midwifery groups, who
still regard epidural analgesia as undesirable interference. Let us
hope that this latest evidence will receives better attention.
1. Halpern SH, Leighton BL, Ohlsson A, Barrett JFR, Rice A. Effect of
epidural vs parenteral opioid analgesia on the progress of labor. JAMA
2. Zhang J. Klebanoff MA. DerSimonian R. Epidural analgesia in association
with duration of labor and mode of delivery: a quantitative review. Am J
Obstet Gynecol 1999:180:970-7.
3. Leighton BL, Halpern SH. The effects of epidural analgesia on the
progress of labor, maternal and neonatal outcomes: a systematic review. Am
J Obstet Gynecol 2002;186:S69-77.
4. 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.
5. Reynolds F, Russell R, Porter J, Smeeton N. Does the use of low dose
bupivacaine infusion increase the nornal delivery rate? International
Journal of Obstetric Anesthesia 2003; 12: 156-163.
6. Thalme B, Belfrage P, Raabe N. Lumbar epidural analgesia in labour: I.
Acid-base balance and clinical condition of the mother, fetus and newborn
child. Acta Obstet Gynecol Scand 1974;53:27-35.
7. Pearson JF, Davies P. The effect of continuous lumbar epidural
analgesia upon fetal acid-base status during the second stage of labour. J
Obstet Gynaecol Br Commonw 1974;81:975-9.
8. Zador G, Nilsson BA. Low dose intermittent epidural anaesthesia with
lidocaine for vaginal delivery. Acta Obstet Gynecol Scand 1974; Suppl
9. 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: 1344-1353.
10. Moss L. Midwives want investigation into birthing procedures.
http://news.scotman.com.latest.cfm 20 May 2004
Competing interests: No competing interests