Perhaps one of the most hotly debated topics in obstetrics relates to the possible effects of epidural analgesia on the progress of labor and incidence of operative delivery. There is much misunderstanding about epidural analgesia, due in part to the lack of controlled trials and differing definitions of concepts, such as fetal stress, hypotension and even the term epidural itself. This debate is also due to the fact that emotions run so high on this issue that it is sometimes difficult to look at it objectively.
It is challenging and confusing to sort through the hundreds of articles in the medical literature regarding the effect of epidural analgesia on labor and delivery. Much of the confusion regards the marked differences in study design and the myriad of potentially confounding variables, such as the exact method and timing of epidural placement, the content and amount of the medication and, perhaps most importantly, the obstetrical management.
Some studies have demonstrated that epidurals cause a higher incidence of cesareans and operative delivery but there are studies that do not show this. Poor study design, investigator bias and old or improper anesthetic technique most likely contribute to many of the reports of "harmful" effects of epidural analgesia on the progress and outcome of labor. It could be that many of the purported harmful effects of labor epidural analgesia result from patient factors (women having abnormal labors are more likely to request epidural block) and obstetrical interventions and not from the analgesic technique itself.