Effects of epidural analgesia on outcomes for trial of labour after Caesarean section (TOLAC)
Abstract Number: F-14
Abstract Type: Original Research
Trial of labour after Caesarean section (TOLAC) is on the decline, related in part to reports of increased maternal morbidity (particularly uterine rupture). Caesarean section (CS) rates of 25% in the UK and over 31% in the USA, have prompted reviews looking at factors influencing successful vaginal birth after CS (VBAC).(1)
Retrospective case-note review of planned TOLAC in our institution, over the last 5 years. Onset of labour, prostaglandin/oxytocin use, type of analgesia, mode of delivery, scar complications and neonatal outcomes were recorded. Data was analysed using Prism Graph-pad software (two-tailed Fisher Exact and Chi-squared tests).
• 324 women underwent TOLAC and 140(43.2%) used epidural analgesia for labour
• 221(68.2%) delivered vaginally and 103(31.8%) required emergency CS. Of the successful vaginal deliveries 169(76.5%) were normal and 52(23.5%) were instrumental
• In the group achieving vaginal delivery, epidural was associated with a significantly higher chance of instrumental delivery [31/81(38.3%) vs 21/140(15.0%) p=0.0002]
• Epidural was associated with a significantly higher use of oxytocin augmentation [81/140(58%) vs 44/184(24%) p=0.0001] and a significantly lower successful VBAC rate [81/140(57.9%) vs 140/184(76.1%) p=0.0008]
• Epidural was not associated with an increased risk of scar dehiscence [1/140(0.71%) vs 3/184(1.63%) p=0.64] or uterine rupture [2/140(1.4%) vs 0/184(0%) p=0.19]
• There were no significant differences in neonatal outcome related to epidural use. There were two cases of uterine rupture giving an overall incidence of 6.2 per 1000. (One case was associated with hypoxic ischaemic encephalopathy [HIE] in a patient with an epidural and oxytocin augmentation)
Rates of vaginal delivery (68.2%) and scar rupture (6.2 per 1000) are similar to those described in previous literature(1)(2). Epidural analgesia was not associated with an increased risk of scar complications, but was associated with significantly lower chance of successful VBAC and a higher chance of instrumental vaginal delivery. These outcomes may be a direct consequence of epidural use or may relate to preferential use of epidural in longer, more complex labours requiring oxytocin augmentation.
1.Shanks AL, Cahill AG. Delivery after prior cesarean: success rate and factors. Clin Perinatol 2011 Jun; 38(2): 233-45
2.Varma R, Gupta JK, Smith GCS. Birth after previous Caesarean birth. RCOG Green-top Guideline No 45.http://www.rcog.org.uk/files/rcog-corp/GTG4511022011.pdf