Ultrasound Assessment of DILAPAN-S

On admission for induction, study participants assigned to each group underwent continuous cardiotocography for 20 minutes prior to placement of the Dilapan-S rods (rod size: 4 x 65mm). Placement of the Dilapan-S rods was limited to three physicians with the majority placed by the primary investigator. Placement was completed in a sterile manner under direct visualization and in accordance with the manufacturer's guidelines. The number of rods placed varied per individual and was based on the discretion of the physician. Each participant allocated to the Dilapan-S with saturated gauze group received placement of one, 4x4 inch gauze saturated with 10 cc of normal saline and placed at the level of the external os. Immediately after placement of the Dilapan-S rods, the study participant was asked to complete a patient satisfaction survey.

Pre-specified transvaginal ultrasound assessment was performed at hours 3, 6, 8, and 12 post Dilapan-S placement using a GE Voluson E10 machine with a transvaginal GE RIC 5-9D transducer. Performance of the ultrasound evaluation was limited to the primary investigator and two co-authors of the study. After completion of the 12-hour ultrasound, the Dilapan-S rods and gauze, if used, were removed as per the manufacturer's instructions. The participant was then asked to complete a post Dilapan-S patient satisfaction survey.

Inclusion criteria

• Pregnant individuals at gestational age 37 weeks or greater.
• Scheduled medical or elective induction at Sentara Norfolk General Hospital.
• Live, singleton IUP.
• Vertex presentation.
• Intact membranes.
• Bishop score of 6 or less.

Exclusion criteria

• Unwilling or unable to provide consent.
• Intrauterine fetal demise
• Contraindications to vaginal delivery.
• BMI > 45
• Vaginal bleeding
• Clinically evident genital tract infection