Effects of epidural analgesia: some questions and answers.

The effects of epidural analgesia on first labors have been studied by Thorp and colleagues. One study has been published and is the subject of a question-and-answer discussion, presented here. In this study 711 consecutive nulliparous women at term, with spontaneous onset of labor and cephalic presentation, were divided into one group (n = 447) who received epidural analgesia in labor and another group (n = 264) who received narcotics or no analgesia. The frequency of cesarean section for dystocia was significantly greater (p less than 0.005) in the epidural group (10.3%) than in the nonepidural group (3.8%), even after selection bias was corrected and the variables of maternal age and race; gestational age; cervical dilatation on admission; use, duration, and maximum infusion rate of oxytocin; labor duration; presence of meconium; and birth weight were controlled. For both groups the frequency of cesarean section for fetal distress was similar (p less than 0.20), and the frequency of low Apgar scores at 5 minutes and cord blood gas values showed no significant differences. The authors concluded that "epidural analgesia in labor may increase the incidence of cesarean section for dystocia in nulliparous women".