Participants randomized to the "Immediate" or control arm (voiding within five minutes of cervical assessment), will undergo any indicated trans-abdominal ultrasound imaging and preparations for vaginal ultrasound (including readying the probe and preparing the exam table for lithotomy position) prior to using the restroom. The participant will be instructed to proceed to the restroom to empty her bladder completely. A synchronized clock will be placed in the restroom, and the patient will be asked to note the time that she completes voiding. This will be confirmed by the research staff by noting the time the participant enters and exits the restroom. Vaginal ultrasound and cervical assessment will then be performed immediately upon return to the ultrasound room (within a maximum of 5 minutes from voiding time).

Participants randomized to the "Interval" or experimental arm (cervical assessment 15 minutes or more after voiding) will be notified of their allocation and asked to immediately use the rest room and attempt to void completely. A synchronized clock will be located in this restroom, and each participant will be asked to note the time that she completes voiding. This will be confirmed by the research staff by noting the time the participant enters and exits the restroom. The participant will return to the waiting room or ultrasound room. Any indicated trans-abdominal ultrasound imaging will be performed, and preparations will be made for the vaginal ultrasound. The participant will be asked not to void prior to the vaginal ultrasound. Cervical assessment will take place at a minimum of 15 minutes from voiding time

Participants randomized to the "Interval" arm (cervical assessment 15 minutes or more after voiding) will be notified of their allocation and asked to immediately use the rest room and attempt to void completely. A synchronized clock will be located in this restroom, and each participant will be asked to note the time that she completes voiding. This will be confirmed by the research staff by noting the time the participant enters and exits the restroom. The participant will return to the waiting room or ultrasound room. Any indicated trans-abdominal ultrasound imaging will be performed, and preparations will be made for the vaginal ultrasound. The participant will be asked not to void prior to the vaginal ultrasound. Cervical assessment will take place at a minimum of 15 minutes from voiding time.

Focal myometrial contraction as defined by transvaginal ultrasound findings:

• Thickening of the myometrial portion of the uterine wall visualized as two distinctly different areas of echogenicity
• An unusually long-appearing cervix (possibly more than 50 mm) with an S-shaped endocervical canal and apparent internal os located appreciably cephalad
• Asymmetric anterior and posterior lower uterine segment widths cephalad to apparent internal os
• The thickening is transient.

The location of focal myometrial contractions in relation to the internal cervical os is defined by:

• Distance from internal os to caudal-most portion of focal myometrial contraction (measured with a curved line)..
• Proportion that lie immediately adjacent to the internal cervical os.