Correspondence to:
Pro Q. Luo, Department of Obstetrics, Women’s Hospital, Zhejiang
University School of Medicine, Hangzhou, 310006, China; (E-mail:
luoq@zju.edu.cn)
Dr. B. Zhao Department of Obstetrics, Women’s Hospital, Zhejiang
University School of Medicine, Hangzhou, 310006, China (E-mail:
zhaobh@zju.edu.cn)
Running title: Delivery prediction models, intrapartum
ultrasound
ABSTRACT
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.
Key
words: Prediction
model, intrapartum ultrasound, angle of progression,
midline
angle,
vaginal delivery, fetal occiput rotation