[Epidural analgesia and the rate of cesarean delivery]

To assess the influence of epidural analgesia on the increased rate of cesarean delivery and to analyze associated factors.

Prospective study enrolling 1,714 women in labor to whom epidural analgesia was offered; 719 received epidural analgesia and 995 did not. We recorded age, weight, height, parity, gestational age, duration of labor, manner of onset of labor, delivery, birth weight, Apgar score and pH in the umbilical artery and vein. Student t, Hotteling's t2 and chi-squared tests were used to compare the results. Multiple logical regression analysis was used to determine the variable or variables having the most effect on the rate of cesarean delivery.

Labor lasted longer in the group of women who received epidural analgesia than in those who did not (234 +/- 90 versus 181 +/- 43 minutes) and the epidural group had significantly higher rates of induced labor (50% versus 15%), instrument-assisted delivery (19% versus 5%) and cesarean delivery (21% versus 8%). Cesarean sections were more frequent among women whose labor was induced and in nulliparous women in both groups. Logical regression analysis showed that epidural analgesia was the most significant variable affecting delivery by cesarean section. The next most influential variable was induction of labor. Parity was not significantly related to delivery by cesarean.

Epidural analgesia increased the likelihood of cesarean delivery in our study. The same factors that most often encourage women to accept epidural analgesia (induced labor, greater pain, prolonged labor, etc.) may predict increased likelihood of cesarean delivery.