Predictors of breakthrough pain during labor epidural analgesia.

UNLABELLED: Parturients who receive labor epidural analgesia may experience breakthrough pain that requires supplemental medications. We investigated the factors associated with breakthrough pain. This prospective observational study included 1963 parturients who received epidural analgesia. Subjects were categorized into two groups on the basis of the number of episodes of breakthrough pain: the Recurrent Breakthrough Pain (RBP) group experienced three or more episodes. Univariate and multivariate regression analyses were used to evaluate factors associated with the RBP group. By multivariate analysis, nulliparity, heavier fetal weight, and epidural catheter placement at an earlier cervical dilation were found to be independently associated with the RBP group. These factors may predict which parturients' analgesia may be complicated by breakthrough pain. Parturients who received a combined spinal/epidural technique were less likely to be associated with the RBP group. The combined spinal/epidural technique may be superior to conventional epidural anesthesia, because breakthrough pain occurred less often. It is interesting to note that the characteristics that are associated with the RBP group are similar to those that have been associated with increased severity of maternal pain. IMPLICATIONS: Nulliparity, heavier fetal weight, and epidural catheter placement at an early cervical dilation are predictors of breakthrough pain during epidural labor analgesia. The combined spinal/epidural technique may be associated with a decreased incidence of breakthrough pain.