Early Compared With Late Neuraxial Analgesia in Nulliparous Labor Induction

Women in early labor frequently request pain medication. Obstetricians may prescribe narcotics (administered as an intravenous (IV) or intramuscular (IM) injection). However, IV or IM narcotics provide incomplete pain relief and have maternal and fetal/neonatal side effects, e.g., maternal drowsiness, respiratory depression, nausea, vomiting, and neonatal respiratory depression. Other obstetricians allow their patients to request early neuraxial (spinal or epidural) analgesia. The results of several studies comparing patients who received epidural versus IV/IM narcotic labor analgesia (not specifically in early labor)suggest that initiation of early neuraxial analgesia may be associated with higher Cesarean delivery rates. It has been hypothesized that epidural/spinal local anesthetics may induce pelvic musculature relaxation leading to failure of fetal descent and rotation. However, early pain may be a marker for other factors that increase the risk of Cesarean delivery, e.g., large or malpositioned baby, or dysfunctional labor. Whether or not early neuraxial analgesia (particularly if narcotic based, which would not cause pelvic muscle paralysis) compared to IV/IM narcotics, adversely affects the outcome of labor has not been studied in a randomized, prospective fashion. The purpose of this study is to compare Cesarean and forcep delivery rates, and quality of pain relief, in first-time mothers undergoing induction of labor who receive neuraxial versus IV/IM analgesia for early labor (cervical dilation < 4 cm).