Background: This study was conducted to evaluate the uterine artery Doppler velocimetry (UADV) during peak uterine contraction in order to predict preterm labour in Iranian women with a normal cervical length. Materials and Methods: This cohort study was conducted at Shariati Hospital within an interval of 1 year between January 2016 and January 2017. One hundred women within gestational age <24 weeks and preterm uterus contraction were enrolled. UADV during peak uterine contraction was evaluated by a perinatologist. Their flow velocity waveforms were recorded (during three consecutive uterine contractions), and the mean for uterine artery doppler pulsatility index (PI) was documented. Results: One hundred cases with the mean age of 31 ± 4.8 years were enrolled in this study. From this selection, eight (8%) cases delivered during the first 48 h of admission and 13 (13%) during the first 7 days. The mean gestational age and the PI were significantly different between cases who delivered during the first 48 h and those who failed to do so. The correlation coefficient between PI and gestational age was r = 0.2, P = 0.02. For women who delivered within the first 7 days, the mean velocity and the PI were considered as significant variables for predicting preterm birth. At last, similar to the first group, for those women who delivered within the first 14 days, the PI was the only predicting factor for preterm birth. Conclusion: This study concludes that the mean PI of uterine artery during peak contractions can be considered as a strong predictor of delivery in preterm labour in women with normal cervical length.