The Role of Ultrasound in the Prediction of Successful Induction of Labour

Background: So far, there has not been conducted the study in Iran about the role of ultrasound in the prediction of successful induction of labour. Therefore, the aim of this study was to investigate the role of sonographic parameters that may help clinicians to improve the prediction of the outcome of induction and need for ripening of cervix before induction. Materials and Methods: In this prospective study, the number of 298 singleton pregnancies that attended for the induction of labour at Shariati and Arash Hospitals in 2017 was evaluated. Immediately before the induction, transvaginal sonography was performed for the measurement of cervical length and posterior cervical angle, and a transabdominal scan was carried out to determine the position of the foetal occiput. Cox proportional hazard model was used for determination of the effects of independent predictor variables on the induction-to-delivery time. Results: The most common indication for the induction was movement reduction and prolonged pregnancy with 20.5% and 18.5% of cases, respectively. The mean of posterior cervical angle in patient delivered vaginally was 124 +/- 18 and in patient delivered by caesarean section was 100 +/- 26.5 (P < 0.001). The sensitivity, specificity, positive predictive value and negative predictive value of sonography compared Bishop score for the likelihood of vaginal delivery within 24 h and was 93.98%, 47.56%, 75% and 82.52%, respectively. Conclusion: The use of parameters of sonographic to predict the outcome of induction enables the clinician to present precise information to mothers and plan for the further management of the pregnancy.