DOES EARLY ADMINISTRATION OF EPIDURAL ANALGESIA AFFECT OBSTETRIC OUTCOME IN NULLIPAROUS WOMEN WHO ARE RECEIVING INTRAVENOUS OXYTOCIN

Background: Some studies suggest that epidural analgesia prolongs labo r and increases the incidence of cesarean section, especially if it is administered before 5 cm cervical dilation. The purpose of the curren t study was to determine whether early administration of epidural anal gesia affects obstetric outcome in nulliparous women who are receiving intravenous oxytocin. Methods: Informed consent was obtained from hea lthy nulliparous women with a singleton fetus in a vertex presentation , who requested epidural analgesia while receiving intravenous oxytoci n at at least 36 weeks' gestation. Each patient was randomized to rece ive either early or late epidural analgesia. Randomization occurred on ly after the following conditions were met: (1) the patient requested pain relief at that moment, (2) a lumbar epidural catheter had been pl aced, and (3) the cervix was at least 3 but less than 5 cm dilated. Pa tients in the early group immediately received epidural bupivacaine an algesia. Patients in the late group received 10 mg nalbuphine intraven ously. Late-group patients did not receive epidural analgesia until th ey achieved a cervical dilation of at least 5 cm or until at least 1 h had elapsed after a second dose of nalbuphine. Results: Early adminis tration of epidural analgesia did not prolong the interval between ran domization and the diagnosis of complete cervical dilation, and it did not increase the incidence of malposition of the vertex at delivery. Also, early administration of epidural analgesia did not result in an increased incidence of cesarean section or instrumental vaginal delive ry. Thirteen (18%) of 74 women in the early group and 14 (19%) of 75 w omen in the late group underwent cesarean section (relative risk for t he early group 0.94; 95% confidence interval 0.48-1.84). Patients in t he early group had lower pain scores between 30 and 120 min after rand omization, and were more likely to experience transient hypotension. I nfants in the late group had lower umbilical arterial and venous blood pH and higher umbilical arterial and venous blood carbon dioxide tens ion measurements at delivery. Conclusions: Early administration of epi dural analgesia did not prolong labor or increase the incidence of ope rative delivery, when compared with intravenous nalbuphine followed by late administration of epidural analgesia, in nulliparous women who w ere receiving intravenous oxytocin.