Background: Although epidural analgesia (EA) is a popular and effective method for pain relief during labor, significant controversy exists in terms of the impact of EA on labor outcomes and the best time for initiation of EA. Here, we aim to explore the effects of early initiation EA on the labor process in nulliparous at-term pregnant women.
 Methods: A total of 240 nulliparous women enrolled in this study. The early epidural (EE) group (n=120) consisted of women in the latent phase of labor and the late epidural (LE) group (n=120) were in the active phase of labor. Each group received 16 ml of 0.125% preservative-free isobaric bupivacaine with 50 µg fentanyl (total: 17 ml) as a primary bolus dose in the epidural space for labor analgesia and an intermittent bolus of 5-10 ml of the primary solution was administered via a catheter. The length of labor, rate of cesarean section (CS), neonatal well-being, and infant Apgar scores were recorded.
 Results: There were no statistically significant differences between the two groups regarding the duration of the first (p=.43) and second (p=.54) phases of labor. No statistically significant differences were observed between the two groups in terms of the rate of CS (p=.21), causes for CS (p=.24), and neonatal Apgar scores (p=0.84).
 Conclusion: Initiation of EA during early labor did not result in increased CS or instrumental vaginal deliveries, and did not prolong labor duration.