The course of labor with and without epidural analgesia

Our purpose was to measure effects of epidural analgesia on labor compared with boluses of meperidine in a cohort of women with similar clinical circumstances.

One hundred ninety-nine nulliparous women who were delivered spontaneously at term and who received oxytocin for labor augmentation before the initiation of analgesia were identified for analysis. All these women were managed in a low-risk labor unit according to a standardized protocol. This management protocol encouraged early amniotomy and the use of oxytocin when ineffective labor was diagnosed.

The demographic characteristics of the two study groups were similar with respect to age, height, weight, and maternal age. The two groups had the same cervical dilatation on admission (3.3 cm) and at the time of analgesia administration (4.1 vs 4.2 cm), indicating similar progress of labor before oxytocin administration. The length of the active phase of labor was longer in the epidural group (7.9 vs 6.3 hours, p = 0.005), as was the second stage (60 vs 48 minutes, p = 0.03). The mean and maximal rates of oxytocin infusion were similar between the two study groups; however, the amount of oxytocin required for each centimeter of cervical change was more in the epidural group (22 vs 16 mU per cm of cervical change, p = 0.009). Neonatal outcomes were unaffected by the type of labor analgesia.

Epidural analgesia decreases uterine performance during oxytocin-stimulated labor, resulting in an increase in the length of the first and second stages of labor.