Cheng Chen

and 11 more

Objective: To develop the prediction models for identifying fetal occiput rotation and vaginal delivery based on intrapartum sonographic findings. Design: Prospective observational study. Setting: Hangzhou, China. Population: Nulliparous women with a singleton cephalic presentation at term. Methods: Serial intrapartum ultrasonography were performed in the latent phase (T1) and every three hours after that (T2, T3 and T4). The managing clinicians performed paired digital vaginal examinations to assess labor progress. Main Outcome Measures: Delivery mode and successful internal fetal head rotation to the occiput anterior (OA) position. Results: 614 women were included, of whom 524 underwent vaginal delivery, and 90 required cesarean section. The percentage of women with fetuses in non-occiput anterior position at the latent phase was 53.9% (331 cases), as 257 women underwent spontaneous rotation to OA position before delivery, 74 were with persistent occiput posterior or transverse position. We developed a model on the basis of the maternal height and middle angel to predict the spontaneous fetal occiput rotation, with the area under the receiver operating characteristic curve (AUC) was 0.667 (95%CI 0.583-0.751). Moreover, a prediction model based on the maternal height and angle of progression to evaluate whether women underwent vaginal delivery was also developed, of which the AUC was 0.738(95% CI: 0.763-0.793). Both models showed satisfactory calibration. Conclusion: Simple models based on maternal characteristics and intrapartum ultrasound findings might provide useful information for predicting vaginal delivery and internal fetal occiput rotation.