Comparing the Effects of Paracetamol and Pethidine on First-stage Labor Pain Relief and Their Maternal and Neonatal Complications

Introduction: The pain relief effect of Paracetamol, as a safe analgesic drug in labor, compared to Pethidine, as a well-known analgesic drug, need to be more evaluated. Objective: This study aims to compare the effects of Paracetamol and Pethidine on the first-stage labor pain relief and neonatal and maternal complications. Materials and Methods: This single-blind, parallel group, randomized clinical trial conducted on 100 nulliparous pregnant women referred to a maternity hospital in Rafsanjan Iran in 2018 who were selected using a convenience sampling method and by assigned into two groups Paracetamol (n=49, receiving 100 mg intravenous Paracetamol) and Pethidine (n= 51, receiving 50 mg intravenous Pethidine) using the minimization method. The drugs were administered when there was at least a 4-cm cervical dilation. Maternal complications and infant’s 1 and 5-min the Apgar scores and ability to breastfeed were evaluated. Pain intensity measured by the Visual Analogue Scale (VAS) and compared using two-way repeated measures ANOVA before and 30 minutes, 1, 2, 3 and 4 hours after drug administration.  Results: There were no significant differences between the two groups in term of age, body mass index, and gestational age, and no significant difference in pain intensity in any groups among the time points. Maternal complications were significantly lower in the Paracetamol group than in the Pethidine group; however, the difference was statistically significant only in terms of nausea (P=0.04). Infants’ breastfeeding ability was significantly better in Paracetamol group than in the Pethidine group (P=0.04). The results of two-way ANOVA showed that the mean VAS score was not significantly different between the two groups. Conclusion: Paracetamol can alleviate the first-stage labor pain similar to Pethidine, but with fewer maternal and neonatal complications.