Timing of initiating epidural analgesia and mode of delivery in nulliparas: a retrospective experience using ropivacaine.

BACKGROUND

The timing of initiation of epidural analgesia and its causal relationship with mode of delivery is controversial. This retrospective investigation reviews and determines whether early initiation of epidural analgesia in nulliparous women influences the rate of cesarean sections as well as other obstetric outcome measures.

METHODS

The nursing records of 1623 parturients who received epidural analgesia were retrospectively reviewed. Of these, 704 nulliparous parturients who presented in spontaneous labor or had spontaneous rupture of the membranes and received epidural analgesia with a regimen of ropivacaine and fentanyl were included in this study. All parturients received the epidural protocol following their first request. Parturients were divided into early (n = 457) and late (n = 247) groups according to cervical dilatation < 3 cm and > or = 3 cm, respectively, when epidural analgesia was initiated. The mean primary cesarean section rate during the research period was calculated from the monthly report of the department of obstetrics and gynecology.

RESULTS

The mean primary cesarean section rate in the institution was 23.6% during the research period. The overall cesarean section rate was 13.4% (n = 704) in the studied groups. The early group required more top-up epidural anesthetic boluses, and had a higher cesarean section rate than the late group (16.4% vs. 7.7%, p = 0.002). However, the cesarean section rates of both groups were lower than the mean primary cesarean section rate. No difference was observed between groups in the percentage of arrested labor as the primary indication for cesarean section. Early epidural analgesia shortened the duration of the active phase of the first stage of vaginal delivery. No difference was observed between groups in the duration of the second stage or the instrumental vaginal delivery rate.

CONCLUSIONS

The administration of epidural analgesia with a regimen of ropivacaine and fentanyl should not be delayed until cervical dilatation reaches 3 cm in nulliparas who are in spontaneous labor or have spontaneous rupture of the membranes. The timing of epidural analgesia should be determined on an individualized basis.