the duration of the third stage of labor and related factors

background: third stage of labor has been defined as the most dangerous stage. due to the importance of the third stage, this study was performed in order to determine its length and related factors. materials and methods: this research is a cross sectional study which was carried out on 1000 deliveries in shabihkhani hospital (kashan-iran). inclusion criteria consist of gestational age of higher than 20 weeks, singleton pregnancy, and vaginal delivery without any instrument. findings: the mean, median and standard deviation of the third stage of labor were 6.03, 5 and 5.15 minutes respectively. the finding also showed that there was a significant association between para, induction of labor, use of analgesic drugs during labor (pethidin), and umbilical drainage for third stage management (p < 0.05). there was no significant association between a history of abortion, gestational age and third stage management (oxytosine). conclusions: the use of induction, analgesic drugs during labor and umbilical drainage prolonged the third stage of labor, but multiparity decreased the duration of this stage. the diagnosis of these factors is recommended in order to predict and prevent the occurrence of the third stage dangers.