Anesthesia and the progress of labour.

Abstract

The last decade has seen a remarkable advance in our understanding of the effects of regional analgesia on the progress and outcome of labour. In particular, the appearance of several well conducted prospective, randomized trials have helped confirm the opinion of most anesthesiologists and a growing number of obstetricians, that epidural analgesia only minimally lengthens labour and does not increase the risk of cesarean section. But the extraordinary methodological complexities of studying this unblindable treatment in patients who are anything but ambivalent about whether or not they receive it ensures the debate will continue. It is perhaps time to move away from outcome studies and on to investigations of the putative mechanisms of any effects epidural analgesia may have on the labour and delivery process. It is also vital to place greater emphasis on the interaction between obstetrical practice, analgesic technique, and the patient. There may be important differences between subsets of patients with regard to their risk of cesarean section and the effect epidural analgesia may have on this risk. This is almost certainly true for certain obstetrical practices. Only by an appreciation of the actual physiology of epidural analgesia in the context of obstetrical care and the labour process itself will one of the longest running debates in anesthesiology come to an end.