The goal of this observational prospective study is to assess the change in Dilapan-S rod diameters using transvaginal ultrasound over a period of 12 hours in term women undergoing induction of labor.

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

Pregnant individuals at term undergoing labor induction at single academic institution.

Study protocol, statistical analysis plan, informed consent form were made available. Results from the study will be available to the manufacturer (Medicem) after statistical analysis is completed and will not be shared with the manufacturer during study execution. The manufacturer company will not be involved in data analysis and all data will be independently analyzed by HADSI. The results of this study will be presented at conferences or published in a peer-review journal.

1-2 months after conclusion of study

Results and statistical analysis will be available at the conclusion of the study