Tehran University of Medical Sciences Acta Medica Iranica 0044-6025 60 3 2022 03 14 150 155 Masoomeh Nataj Majd Department of Anesthesiology, Arash Women's Hospital, Tehran University of Medical Sciences, Tehran, Iran. Maryam Farid Mojtahedi Department of Obstetrics and Gynecology, Arash Women's Hospital, Tehran University of Medical Sciences, Tehran, Iran. Arman Taheri Department of Anesthesiology and Pain, Imam Khomeini Medical Center, Tehran University of Medical Sciences, Tehran, Iran. Mehdi Sanatkar Department of Anesthesiology and Pain, Farabi Hospital, Tehran University of Medical Sciences, Tehran, Iran Nader Ali Nazemian Yazdi Department of Anesthesiology, Amir A’lam Hospital, Tehran University of Medical Sciences, Tehran, Iran 2021 11 21 2021 12 26 Epidural analgesia (EA) is one of the best pain relief for many pregnant women in labor. This study was conducted to evaluate the effect of epidural analgesia provided by a combination of bupivacaine plus meperidine or fentanyl on the mother, fetus, and labor process in term nulliparous women. A total of 558 nulliparous women were randomized into two groups of 279 subjects. The BF (Bupivacaine-Fentanyl) group received 16 ml bupivacaine 0.125% plus 50 mg fentanyl as a loading dose; then, an intermittent bolus of the same solution was administered once the patient requested analgesia. The BM (Bupivacaine-Meperidine) group received a loading dose of 16 ml bupivacaine 0.125% plus 20 mg meperidine followed by an intermittent bolus of the same solution if the patient requested analgesia. The time of labor phases 1 and 2 and the incidence of side effects were recorded. After the intervention, the pain score was significantly lower in the meperidine group compared to the fentanyl group during labor (P=0.006). The duration of the active phase of labor (P=0.04) and the rate of cesarean section (P=0.01) were significantly higher in the fentanyl group compared to the meperidine group. The duration of the second stage of labor was not significantly different between the two groups (P=0.24). Apgar score was significantly higher in the meperidine group. This study found that epidural meperidine could be a suitable alternative to fentanyl for improving pain relief and shortening the active phase of delivery without increasing the risk of the neonatal low Apgar score. https://acta.tums.ac.ir/index.php/acta/article/view/9801