Does epidural analgesia cause dystocia?

To analyze the effects of epidural analgesia for labor when dystocia occurs. Retrospective cohort study. Academic health center. 641 low risk, nulliparous women in spontaneous labor. 406 (63%) women received epidurals analgesia and 253 (37%) did not. Sixty women (9.4%) required an abdominal delivery for dystocia. Women receiving epidural analgesia were more likely to be white, receive care from an attending physician, need labor augmentation, and deliver a heavier infant. Multivariate analysis identified five variables predictive of dystocia and abdominal delivery: pitocin augmentation odds ratio (O.R.) = 3.9 (2.0 to 7.6), duration of labor more than 20 hours O.R. = 2.4 (1.3 to 4.4), high epidural dose O.R. = 2.2 (1.2 to 4.1), birthweight over 4,000 grams O.R. = 2.0 (1.0 to 4.2), and early placement of epidural O.R. = 1. 9 (1.0 to 3.5). Repeating the regression after excluding the 20 women who developed abnormal labor prior to epidural placement (18 of 20 women had protracted dilatation) demonstrated that pitocin augmentation O.R. = 4.0 (1.8 to 4.), high epidural dose O.R. = 3.0 (1.9 to 6.2), duration of labor greater than 20 hours O.R. = 2.7 (1.3 to 5.7), and birthweight over 4,000 grams O.R. = 2.1 (0. 9 to 4.8) were associated with dystocia. Epidural analgesia appears to be a marker of abnormal labor rather than a cause of dystocia. High concentration anesthetics and epinephrine should be avoided, as they may influence labor. Randomized, controlled trials of this technique will be difficult to do; our work should reassure patients and their clinicians that epidural analgesia does not adversely affect labor.