Effects of epidural fentanyl on labor pain during the early period of the first stage of induced labor in nulliparous women

Background and purpose: It is generally accepted that epidural injection wi th local anesthetics and narcotics administered when the cervix has dilated to a diameter exceeding 4 cm can adequately control labor pain. However, m any nulliparous women still suffer from labor pain for a few hours prior to the administration of epidural analgesia. This study examined the effectiv eness of relief oh labor pain obtained by injection of narcotics epidurally once the labor pain begins and the subject requests analgesia. Methods: Subjects scheduled for induced labour were divided into three grou ps: Group A (n = 60) received 5 x 10(-4)% fentanyl (10-20 mt) administered epidurally to relieve early first-stage labor pain. Group B (n = 60) receiv ed no analgesic in the early first stage of labor. For groups A and B, when cervical dilatation exceeded 4 cm, 10 to 15 mt of 5 x 10(-2)% bupivacaine and 2 x 10(-4)% fentanyl were injected epidurally and a continuous low dosa ge was maintained until full dilatation of the cervix resulted. Group C (n = 198) received no analgesic during the entire labor course. Results: There were no significant differences in the duration of the early period of the first stage of labor, the duration of the late period of the first stage, the duration of the second stage, the Apgar score, or the art erial blood gas of neonates among the three groups. However, group C had a significantly higher cesarean section rate (28.8%) than group A (16.7%) or group B (15%). Pain scores assessed with the Visual Analog Scale (VAS) thro ughout the entire labor course, were lower in group A than in group B; part icularly during the early period of the first stage. The VAS scores in both groups A and B were significantly lower than those in group C during the l ate period of the first stage of labor. Conclusions: The results indicate that once labor pain begins and the subje ct requests analgesia, epidural injection with fentanyl alone can relieve l abor pain during the early period of the first stage. The analgesia does no t cause adverse effects to the mothers or neonates. In addition, the labor course and the method of delivery are not affected.