Epidurals are the most effective form of pain relief during childbirth. However, they are associated with increased rates of instrumental vaginal delivery and associated complications, which might be related to poor motor function (which prevents mothers from pushing during labour). New techniques that preserve motor function could reduce obstetric intervention. Andrew Shennan and Christine MacArthur lead a team of investigators who did a randomised controlled trial to compare two low-dose epidural techniques; combined spinal epidural (injection into the spinal fluid followed by epidural top-ups) and low-dose infusion (epidural given continuously using a pump) with traditional epidural techniques.
The investigators randomly assigned 1054 women requesting epidural pain relief to traditional epidural, low-dose combined spinal epidural, or low-dose infusion epidural. The primary outcome was mode of delivery; secondary outcomes were progress of labour, efficacy of procedure, and the effect of the type of epidural on the newborn.
The rate of normal vaginal delivery increased (from around 35% to 43%) in both the low-dose combined spinal epidural group and in the low-dose infusion group compared with women given traditional epidural. However, babies whose mothers were given low-dose epidural took longer to become vigorous after delivery, and a few of the babies in the low-dose infusion group were more likely to require breathing assistance.
Andrew Shennan and Christine MacArthur comment: "We have shown that there are clear advantages in delivery outcome with low-dose techniques rather than traditional epidurals for analgesia in labour. Pain relief is not compromised. The reduced operative intervention with the low-dose techniques needs to be weighed against possible adverse effects on the neonate. Long-term data are not available yet, but in relation to delivery outcome, continued routine use of traditional epidurals might not be justified."
In an accompanying Commentary (p 2), James Thornton from the University of Leeds, UK, concludes: "The message from this study is clear. Anaesthetists should offer the technique that interferes least with the normal mechanisms of labour, namely either combined spinal epidural or low-dose infusion epidural. These methods offer the best chance of a spontaneous delivery with satisfactory pain control. If the traditional technique is used, women should be informed that they are associated with an increased risk of operative vaginal delivery."
Contact: Mr Andrew H Shennan, Maternal and Fetal Health Research Group, Department of Obstetrics and Gynaecology, 10th Floor North Wing, St Thomas' Hospital, Lambeth Palace Road, LONDON SE1 7EH, UK; T) +44 (0)20 7960 5738; F) +44 (0)20 7620 1227; E) andrew.shennan@kcl.ac.uk
Journal
The Lancet