Related Experiment Video
Updated: Aug 20, 2026
Spinal Sonography for Ultrasound-Guided Lumbar Neuraxial Anesthesia
Published on: January 31, 2025
Bishop score and transvaginal ultrasound for preinduction cervical assessment: a randomized clinical trial
J L Bartha1, R Romero-Carmona, P Martínez-Del-Fresno
1Department of Obstetrics and Gynecology, University Hospital of Puerto Real, Puerto Real, Cadiz, Spain. joseluis.bartha@uca.es
Objective:
To compare transvaginal ultrasound with the Bishop score in assessment of cervical ripening for choice of induction agent.
Methods:
Eighty women were randomized to have preinduction cervical assessment for choice of induction agent based on either Bishop score or transvaginal ultrasound. The primary outcome measure was the percentage of women who were administered prostaglandin as a preinduction agent. The criteria for considering the cervix as unripe and thus for using prostaglandin were either a Bishop score < 6 or a cervical length > 30 mm with cervical wedging of < 30% of the total cervical length. Secondary outcome measures included interval to active phase, interval to delivery and rate of Cesarean section.
Results:
While 85% of women received prostaglandin in the Bishop score group, only 50% of them did in the transvaginal ultrasound group (P = 0.001). The interval to active phase, interval to delivery and rate of Cesarean section were similar in both groups.
Conclusions:
With the suggested cut-off values of a Bishop score < 6 or a cervical length > 30 mm and wedging < 30%, the use of transvaginal ultrasound instead of Bishop score for preinduction cervical assessment to choose induction agent significantly reduces the need for intracervical prostaglandin treatment without adversely affecting the success of induction.