Epidural analgesia

1. Effectiveness of epidural analgesia (EA) for pain relief in labour
Epidural analgesia (or sometimes combined spinal epidural analgesia) is the most effective method for pain relief in labour, compared with inhalational analgesia (Entonox) and pethidine injection. In most observational studies, 90% of women found a satisfactory pain control with EA.

2. How does an EA work?

  • It is performed by an anaesthetist in the labour suite;
  • A thin tube will be passed into the epidural space at the back of the pregnant woman. Anaesthetic medications are administered through this tube. It takes about 10 minutes to set up the EA, and another 10-15 minutes for it to work;
  • The pain relief by the initial dose will wear off after some time. The EA can then be topped up by the midwife through the tube at the epidural space. The repeated top-ups when needed will ensure good pain relief;
  • The tube is removed after the delivery

3. When should an EA be performed?
EA should be performed whenever a labouring woman wants. If induction of labour is needed, it can be performed prior to the induction process to avoid any pain. Early or late initiation of EA does not affect the chances of caesarean section or instrumental vaginal delivery (using forceps or vaccum extraction for childbirth).

4. Does it slow down the labour process?
Meta-analysis studies do not show any difference in the duration of the first stage of labour (between onset of labour and full cervical dilatation) with EA. The overall caesarean rates are also not affected.

5. Does it affect the pushing at second stage of labour?
Meta-analysis studies do show that EA is associated with a longer second stage of labour (between full cervical dilatation and delivery of the baby) by a mean of 15 minutes and a higher chance of requiring instrumental vaginal delivery. However, the author does not share this experience. It is the belief of the author that factors like

  1. (i) only allowing to push when the women had some urge,
  2. (ii) the use of oxytocin at the second stage and
  3. (iii) support of the midwives and obstetricians are all important factors.

6. Potential adverse effects of EA
Like all procedures, EA may be associated with adverse effects, including dural tap during the procedure, immediate side-effects of low blood pressure (hypotension), maternal fever during labour or urinary retention following delivery. These can usually be managed properly with no long-term sequelae. Complications like epidural haematoma or infection can also happen but they are extremely uncommon.

This article is contributed by Dr. T.N. Danny Leung
Updated on 25.09.2020