Abstract: Delivery is a process in which the fetus is descending with the contraction in the maternal birth canal. In addition to monitoring the fetal heart rate, doctors and midwives need to estimate the position, the station , and cervical dilatation through vaginal examination, if necessary, assist the mother to give birth. However, frequent vaginal examinations will not only bring a poor delivery experience to the mother, but also increase the risk of uterine infection. The accuracy of the vaginal examination depends on the experience of the examiner to a large extent. If the assessment is wrong, it may affect the final outcome. In recent years, more and more evidences shows that the accuracy, repeatability and maternal compliance of ultrasound are higher than vaginal examination in managing labor. Dozens of ultrasound parameters have been proposed, which have shown good performance in judging the fetal position, station, rotation and predicting the outcome of delivery. This review summarized recent literatures, in order to objectively analyze the advantages, disadvantages, and future development of ultrasound in labor monitoring.

Key words: Ultrasonography；Vaginal examination；, Labor, obstetric；, Labor stage, first；, Labor stage, second；, Labor presentation