Effect of pethidine on the duration of stages of labour

Background: Shorter labour not only prevents unpleasent memory of delivery but also decreases the probability of uterine atony, post partum hemorrhage and purperal infection. Objective: The aim of this study was to determine the effect of intramuscular pethidine on the duration of stage 1,2 and 3 of labour. Methods: In this clinical trial study, 88 primiparous women with term pregnancy were observed. In all of the cases, labour pains started spontaneously and had fetal and maternal indication for normal vaginal delivery. They were divided into two groups randomly. The first group recieved 75mg IM pethidine and the second group received the same volume of normal saline. Injection was done when cervical dilatation reached to 5cm (at the begining time of active phase of labour). Findings: The duration from drug administration until 10cm cervical dilatation, and also until fetus and placental expulsion were shorter in pethidine group and there were statistically significant difference between two groups (P0.05). Conclusion: Pethidine in an appropriate dosage is an effective drug in decreasing the length of stage 1,2 and 3 of labour, and has no effect on uterus contractions.